diff --git a/NEWS b/NEWS
index 79fdb8ef..7b75972c 100644
--- a/NEWS
+++ b/NEWS
@@ -8,14 +8,14 @@ GNU Bison NEWS
   and yyparse.  The %lex-param, %parse-param, and %param directives
   support one or more arguments.  Instead of
 
-      %lex-param   {arg1_type *arg1}
-      %lex-param   {arg2_type *arg2}
-      %parse-param {arg1_type *arg1}
-      %parse-param {arg2_type *arg2}
+    %lex-param   {arg1_type *arg1}
+    %lex-param   {arg2_type *arg2}
+    %parse-param {arg1_type *arg1}
+    %parse-param {arg2_type *arg2}
 
   one may now declare
 
-      %param {arg1_type *arg1} {arg2_type *arg2}
+    %param {arg1_type *arg1} {arg2_type *arg2}
 
 ** Java skeleton improvements
 
@@ -38,10 +38,10 @@ GNU Bison NEWS
   the generated files.  This is especially useful to avoid collisions
   with identifiers in the target language.  For instance
 
-      %token FILE for ERROR
-      %define api.tokens.prefix "TOK_"
-      %%
-      start: FILE for ERROR;
+    %token FILE for ERROR
+    %define api.tokens.prefix "TOK_"
+    %%
+    start: FILE for ERROR;
 
   will generate the definition of the symbols TOK_FILE, TOK_for, and
   TOK_ERROR in the generated sources.  In particular, the scanner must
@@ -68,6 +68,47 @@ GNU Bison NEWS
   allow the programmer to prune possible parses based on the values of
   runtime expressions.
 
+* Noteworthy changes in release ?.? (????-??-??) [?]
+
+** Future changes:
+
+  The next major release will drop support for generating parsers in K&R C,
+  and remove the definition of yystype (removal announced since Bison
+  1.875).
+
+** The generated header is included (yacc.c)
+
+  Instead of duplicating the content of the generated header (definition of
+  YYSTYPE, yyltype etc.), the generated parser now includes it, as was
+  already the case for GLR or C++ parsers.
+
+** Headers (yacc.c, glr.c, glr.cc)
+
+*** Guards
+
+  The generated headers are now guarded, as is already the case for C++
+  parsers (lalr1.cc).  For intance, with --defines=foo.h:
+
+    #ifndef YY_FOO_H
+    # define YY_FOO_H
+    ...
+    #endif /* !YY_FOO_H  */
+
+*** New declarations
+
+  The generated header now declares yydebug and yyparse.  Both honor
+  --name-prefix=bar_, and yield
+
+    int bar_parse (void);
+
+  rather than
+
+    #define yyparse bar_parse
+    int yyparse (void);
+
+  in order to facilitate the inclusion of several parser headers inside a
+  single compilation unit.
+
 * Noteworthy changes in release 2.5.1 (2012-06-05) [stable]
 
 ** Future changes:
diff --git a/data/c.m4 b/data/c.m4
index 2b7e9d63..2601d561 100644
--- a/data/c.m4
+++ b/data/c.m4
@@ -604,3 +604,15 @@ typedef struct YYLTYPE
 # define YYLTYPE_IS_TRIVIAL 1
 #endif]])
 ])
+
+# b4_declare_yydebug
+# ------------------
+m4_define([b4_declare_yydebug],
+[[/* Enabling traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG ]b4_parse_trace_if([1], [0])[
+#endif
+#if YYDEBUG
+extern int ]b4_prefix[debug;
+#endif][]dnl
+])
diff --git a/data/glr.c b/data/glr.c
index 1463a9a7..f4efca2c 100644
--- a/data/glr.c
+++ b/data/glr.c
@@ -171,9 +171,11 @@ m4_define([b4_rhs_location],
 # Declaration that might either go into the header (if --defines)
 # or open coded in the parser body.
 m4_define([b4_shared_declarations],
-[b4_percent_code_get([[requires]])[
+[b4_declare_yydebug[
+]b4_percent_code_get([[requires]])[
 ]b4_token_enums(b4_tokens)[
 ]b4_declare_yylstype[
+]b4_c_ansi_function_decl(b4_prefix[parse], [int], b4_parse_param)[
 ]b4_percent_code_get([[provides]])[]dnl
 ])
 
@@ -213,11 +215,6 @@ m4_if(b4_prefix, [yy], [],
 ]b4_defines_if([[#include "@basename(]b4_spec_defines_file[@)"]],
               [b4_shared_declarations])[
 
-/* Enabling traces.  */
-#ifndef YYDEBUG
-# define YYDEBUG ]b4_parse_trace_if([1], [0])[
-#endif
-
 /* Enabling verbose error messages.  */
 #ifdef YYERROR_VERBOSE
 # undef YYERROR_VERBOSE
@@ -417,9 +414,6 @@ dnl We probably ought to introduce a type for confl.
   ]b4_conflicting_rules[
 };
 
-/* Prevent warning if -Wmissing-prototypes.  */
-]b4_c_ansi_function_decl([yyparse], [int], b4_parse_param)[
-
 /* Error token number */
 #define YYTERROR 1
 
@@ -2626,15 +2620,12 @@ m4_if(b4_skeleton, ["glr.c"],
 [b4_defines_if(
 [@output(b4_spec_defines_file@)@
 b4_copyright([Skeleton interface for Bison GLR parsers in C],
-             [2002-2012])
+             [2002-2012])[
 
-b4_shared_declarations
-
-b4_pure_if([],
-[[extern YYSTYPE ]b4_prefix[lval;]])
-
-b4_locations_if([b4_pure_if([],
-[extern YYLTYPE ]b4_prefix[lloc;])
-])
-])])[]dnl
+]b4_cpp_guard_open([b4_spec_defines_file])[
+]b4_shared_declarations[
+]b4_pure_if([], [[extern YYSTYPE ]b4_prefix[lval;
+]b4_locations_if([[extern YYLTYPE ]b4_prefix[lloc;]])])[
+]b4_cpp_guard_close([b4_spec_defines_file])[
+]])])
 m4_divert_pop(0)
diff --git a/data/glr.cc b/data/glr.cc
index 117c7148..9a9d7764 100644
--- a/data/glr.cc
+++ b/data/glr.cc
@@ -226,8 +226,7 @@ b4_copyright([Skeleton interface for Bison GLR parsers in C++],
 
 /* C++ GLR parser skeleton written by Akim Demaille.  */
 
-#ifndef PARSER_HEADER_H
-# define PARSER_HEADER_H
+]b4_cpp_guard_open([b4_spec_defines_file])[
 
 ]b4_percent_code_get([[requires]])[
 
@@ -333,8 +332,6 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 #endif
 
 ]b4_namespace_close[
-
-]b4_percent_code_get([[provides]])[]dnl
-
-[#endif /* ! defined PARSER_HEADER_H */]
-m4_divert_pop(0)
+]b4_percent_code_get([[provides]])[
+]b4_cpp_guard_close([b4_spec_defines_file])[
+]m4_divert_pop(0)
diff --git a/data/yacc.c b/data/yacc.c
index 922a4ebe..56be747a 100644
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -226,6 +226,62 @@ m4_define([b4_declare_parser_state_variables], [b4_pure_if([[
     yytype_int16 *yyes;
     YYSIZE_T yyes_capacity;]])])
 
+
+# b4_declare_yyparse_push_
+# ------------------------
+m4_define([b4_declare_yyparse_push_],
+[[typedef struct ]b4_prefix[pstate ]b4_prefix[pstate;
+enum { YYPUSH_MORE = 4 };
+]b4_pull_if([b4_c_function_decl([b4_prefix[parse]], [[int]], b4_parse_param)
+])b4_c_function_decl([b4_prefix[push_parse]], [[int]],
+  [[b4_prefix[pstate *yyps]], [[yyps]]]b4_pure_if([,
+  [[[int yypushed_char]], [[yypushed_char]]],
+  [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
+  [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])])m4_ifset([b4_parse_param], [,
+  b4_parse_param]))
+b4_pull_if([b4_c_function_decl([b4_prefix[pull_parse]], [[int]],
+  [[b4_prefix[pstate *yyps]], [[yyps]]]m4_ifset([b4_parse_param], [,
+  b4_parse_param]))])
+b4_c_function_decl([b4_prefix[pstate_new]], [b4_prefix[pstate *]],
+                    [[[void]], []])
+b4_c_function_decl([b4_prefix[pstate_delete]], [[void]],
+                   [[b4_prefix[pstate *yyps]], [[yyps]]])dnl
+])
+
+# b4_declare_yyparse_
+# -------------------
+# When not the push parser.
+m4_define([b4_declare_yyparse_],
+[[#ifdef YYPARSE_PARAM
+]b4_c_function_decl(b4_prefix[parse], [int],
+                    [[void *YYPARSE_PARAM], [YYPARSE_PARAM]])[
+#else /* ! YYPARSE_PARAM */
+]b4_c_function_decl(b4_prefix[parse], [int], b4_parse_param)[
+#endif /* ! YYPARSE_PARAM */]dnl
+])
+
+
+# b4_declare_yyparse
+# ------------------
+m4_define([b4_declare_yyparse],
+[b4_push_if([b4_declare_yyparse_push_],
+            [b4_declare_yyparse_])[]dnl
+])
+
+
+# b4_shared_declarations
+# ----------------------
+# Declaration that might either go into the header (if --defines)
+# or open coded in the parser body.
+m4_define([b4_shared_declarations],
+[b4_declare_yydebug[
+]b4_percent_code_get([[requires]])[
+]b4_token_enums_defines(b4_tokens)[
+]b4_declare_yylstype[
+]b4_declare_yyparse[
+]b4_percent_code_get([[provides]])[]dnl
+])
+
 ## -------------- ##
 ## Output files.  ##
 ## -------------- ##
@@ -269,11 +325,6 @@ m4_if(b4_prefix, [yy], [],
 
 ]b4_null_define[
 
-/* Enabling traces.  */
-#ifndef YYDEBUG
-# define YYDEBUG ]b4_parse_trace_if([1], [0])[
-#endif
-
 /* Enabling verbose error messages.  */
 #ifdef YYERROR_VERBOSE
 # undef YYERROR_VERBOSE
@@ -287,34 +338,10 @@ m4_if(b4_prefix, [yy], [],
 # define YYTOKEN_TABLE ]b4_token_table[
 #endif
 
-]b4_percent_code_get([[requires]])[
-]b4_token_enums_defines(b4_tokens)[
-]b4_declare_yylstype[
-]b4_push_if([[
-#ifndef YYPUSH_DECLS
-#  define YYPUSH_DECLS
-struct yypstate;
-typedef struct yypstate yypstate;
-enum { YYPUSH_MORE = 4 };
+]b4_defines_if([[#include "@basename(]b4_spec_defines_file[@)"]],
+               [b4_shared_declarations])[
 
-]b4_pull_if([b4_c_function_decl([[yyparse]], [[int]], b4_parse_param)
-])b4_c_function_decl([[yypush_parse]], [[int]],
-  [[[yypstate *yyps]], [[yyps]]]b4_pure_if([,
-  [[[int yypushed_char]], [[yypushed_char]]],
-  [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
-  [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])])m4_ifset([b4_parse_param], [,
-  b4_parse_param]))
-b4_pull_if([b4_c_function_decl([[yypull_parse]], [[int]],
-  [[[yypstate *yyps]], [[yyps]]]m4_ifset([b4_parse_param], [,
-  b4_parse_param]))])
-b4_c_function_decl([[yypstate_new]], [[yypstate *]], [[[void]], []])
-b4_c_function_decl([[yypstate_delete]], [[void]],
-                   [[[yypstate *yyps]], [[yyps]]])[
-#endif]])
-
-b4_percent_code_get([[provides]])[]dnl
-
-[/* Copy the second part of user declarations.  */
+/* Copy the second part of user declarations.  */
 ]b4_user_post_prologue
 b4_percent_code_get[]dnl
 
@@ -1298,20 +1325,12 @@ yysyntax_error (YYSIZE_T *yymsg_alloc, char **yymsg,
 }
 #endif /* YYERROR_VERBOSE */
 
-]b4_yydestruct_generate([b4_c_function_def])b4_push_if([], [[
+]b4_yydestruct_generate([b4_c_function_def])[
 
-
-/* Prevent warnings from -Wmissing-prototypes.  */
-#ifdef YYPARSE_PARAM
-]b4_c_function_decl([yyparse], [int],
-                    [[void *YYPARSE_PARAM], [YYPARSE_PARAM]])[
-#else /* ! YYPARSE_PARAM */
-]b4_c_function_decl([yyparse], [int], b4_parse_param)[
-#endif /* ! YYPARSE_PARAM */]])b4_pure_if([], [
+]b4_pure_if([], [
 
 b4_declare_scanner_communication_variables])[]b4_push_if([[
 
-
 struct yypstate
   {]b4_declare_parser_state_variables[
     /* Used to determine if this is the first time this instance has
@@ -1976,37 +1995,13 @@ yypushreturn:]])[
 ]b4_epilogue[]dnl
 b4_defines_if(
 [@output(b4_spec_defines_file@)@
-b4_copyright([Bison interface for Yacc-like parsers in C])dnl
+b4_copyright([Bison interface for Yacc-like parsers in C])[
 
-b4_percent_code_get([[requires]])[]dnl
-
-b4_token_enums_defines(b4_tokens)[
-]b4_declare_yylstype[
+]b4_cpp_guard_open([b4_spec_defines_file])[
+]b4_shared_declarations[
 ]b4_pure_if([], [[extern YYSTYPE ]b4_prefix[lval;
-]b4_locations_if([[extern YYLTYPE ]b4_prefix[lloc;]])])dnl
-b4_push_if([[
-#ifndef YYPUSH_DECLS
-#  define YYPUSH_DECLS
-struct ]b4_prefix[pstate;
-typedef struct ]b4_prefix[pstate ]b4_prefix[pstate;
-enum { YYPUSH_MORE = 4 };
-]b4_pull_if([b4_c_function_decl([b4_prefix[parse]], [[int]], b4_parse_param)
-])b4_c_function_decl([b4_prefix[push_parse]], [[int]],
-  [[b4_prefix[pstate *yyps]], [[yyps]]]b4_pure_if([,
-  [[[int yypushed_char]], [[yypushed_char]]],
-  [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
-  [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])])m4_ifset([b4_parse_param], [,
-  b4_parse_param]))
-b4_pull_if([b4_c_function_decl([b4_prefix[pull_parse]], [[int]],
-  [[b4_prefix[pstate *yyps]], [[yyps]]]m4_ifset([b4_parse_param], [,
-  b4_parse_param]))])
-b4_c_function_decl([b4_prefix[pstate_new]], [b4_prefix[pstate *]],
-                    [[[void]], []])
-b4_c_function_decl([b4_prefix[pstate_delete]], [[void]],
-                   [[b4_prefix[pstate *yyps]], [[yyps]]])[
-#endif
-]])
-b4_percent_code_get([[provides]])[]dnl
-])dnl b4_defines_if
+]b4_locations_if([[extern YYLTYPE ]b4_prefix[lloc;]])])[
+]b4_cpp_guard_close([b4_spec_defines_file])[
+]])dnl b4_defines_if
 m4_divert_pop(0)
 m4_popdef([b4_copyright_years])
diff --git a/tests/actions.at b/tests/actions.at
index 8be86f07..84529bef 100644
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -28,14 +28,13 @@ AT_SETUP([Mid-rule actions])
 # instead of being attached to the empty rule dedicated to this
 # action.
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%define parse.error verbose
 %debug
 %{
-# include <stdio.h>
-# include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 %%
 exp:     { putchar ('0'); }
@@ -51,28 +50,15 @@ exp:     { putchar ('0'); }
          { putchar ('\n'); }
    ;
 %%
-static int
-yylex (void)
-{
-  static char const input[] = "123456789";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(123456789)[
 int
 main (void)
 {
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-d -v -o input.c input.y])
 AT_COMPILE([input])
@@ -92,14 +78,13 @@ AT_CLEANUP
 
 AT_SETUP([Exotic Dollars])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%define parse.error verbose
 %debug
 %{
-# include <stdio.h>
-# include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(Var)
 %}
 
@@ -130,21 +115,8 @@ sum_of_the_five_previous_values:
 ;
 
 %%
-static int
-yylex (void)
-{
-  static int called;
-  if (called++)
-    abort ();
-  return EOF;
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([])[
 int
 main (void)
 {
@@ -165,8 +137,8 @@ AT_DATA_GRAMMAR([[input.y]],
 [[
 %{
 # include <stdio.h>
-  static int yylex (void);
-  static void yyerror (char const *msg);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
   typedef struct { int val; } stype;
 # define YYSTYPE stype
 %}
@@ -185,12 +157,7 @@ yylex (void)
   return 0;
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
@@ -204,6 +171,7 @@ AT_PARSER_CHECK([[./input]], [[0]],
 [[6
 ]])
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
@@ -245,7 +213,7 @@ AT_LALR1_CC_IF([%define global_tokens_and_yystype])
 m4_ifval([$6], [[%code provides {]], [[%code {]])
 AT_LALR1_CC_IF([typedef yy::location YYLTYPE;])
 [static int yylex (]AT_LEX_FORMALS[);
-]AT_LALR1_CC_IF([], [static void yyerror (const char *msg);])
+]AT_LALR1_CC_IF([], [AT_YYERROR_DECLARE])
 [}
 
 ]m4_ifval([$6], [%type <ival> '(' 'x' 'y' ')' ';' thing line input END])[
@@ -593,7 +561,8 @@ Parsing FAILED (status 2).
 ]])
 ])
 
-])
+AT_BISON_OPTION_POPDEFS
+])# _AT_CHECK_PRINTER_AND_DESTRUCTOR
 
 
 # AT_CHECK_PRINTER_AND_DESTRUCTOR([BISON-OPTIONS], [UNION-FLAG], [SKIP_FLAG])
@@ -632,7 +601,7 @@ AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [with union])
 # called for $end, and that $$ and @$ work correctly.
 
 AT_SETUP([Default tagless %printer and %destructor])
-
+AT_BISON_OPTION_PUSHDEFS([%locations])
 AT_DATA_GRAMMAR([[input.y]],
 [[%define parse.error verbose
 %debug
@@ -645,8 +614,8 @@ AT_DATA_GRAMMAR([[input.y]],
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
 # define USE(SYM)
 %}
 
@@ -677,25 +646,8 @@ AT_DATA_GRAMMAR([[input.y]],
 start: 'a' 'b' 'c' 'd' 'e' { $$ = 'S'; USE(($1, $2, $3, $4, $5)); } ;
 
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "abcd";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  yylval = input[toknum++];
-  yylloc.first_line = yylloc.last_line = 1;
-  yylloc.first_column = yylloc.last_column = toknum;
-  return yylval;
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([abcd], [[yylval = res]])[
 
 int
 main (void)
@@ -741,6 +693,7 @@ Cleanup: discarding lookahead token $end (1.5-1.5: )
 Stack now 0
 ]])
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
@@ -750,7 +703,7 @@ AT_CLEANUP
 ## ------------------------------------------------------ ##
 
 AT_SETUP([Default tagged and per-type %printer and %destructor])
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%define parse.error verbose
 %debug
@@ -758,8 +711,8 @@ AT_DATA_GRAMMAR([[input.y]],
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(SYM)
 %}
 
@@ -805,22 +758,8 @@ start:
   ;
 
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "abcdef";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([abcdef])[
 
 int
 main (void)
@@ -878,6 +817,7 @@ Cleanup: discarding lookahead token $end ()
 Stack now 0
 ]])
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
@@ -895,6 +835,7 @@ m4_define([_AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN],
   [m4_pushdef([kind], []) m4_pushdef([not_kind], [*])],
   [m4_pushdef([kind], [*]) m4_pushdef([not_kind], [])])
 
+AT_BISON_OPTION_PUSHDEFS([%locations])
 AT_DATA_GRAMMAR([[input]]$1[[.y]],
 [[%define parse.error verbose
 %debug
@@ -907,8 +848,8 @@ AT_DATA_GRAMMAR([[input]]$1[[.y]],
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(SYM)
 %}
 
@@ -950,12 +891,7 @@ yylex (void)
   yylloc.first_column = yylloc.last_column = 1;
   return 0;
 }
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
+]AT_YYERROR_DEFINE[
 
 int
 main (void)
@@ -964,6 +900,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input$1.c input$1.y])
 AT_COMPILE([input$1])
@@ -1010,15 +947,15 @@ AT_SETUP([Default %printer and %destructor are not for error or $undefined])
 #       semantic value, which would be initialized from the lookahead, which
 #       would be destroyed separately.
 #   - For $undefined, who knows what the semantic value would be.
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%debug
 
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(SYM)
 %}
 
@@ -1039,24 +976,8 @@ start:
   ;
 
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "abd";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  yylval = input[toknum++];
-  return yylval;
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([abd], [yylval = res])[
 int
 main (void)
 {
@@ -1064,6 +985,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input])
@@ -1125,14 +1047,15 @@ AT_SETUP([Default %printer and %destructor are not for $accept])
 #     true for $undefined and the error token, so there are three warnings for
 #     %printer and three for %destructor.)
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%debug /* So that %printer is actually compiled.  */
 
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(SYM)
 %}
 
@@ -1153,28 +1076,15 @@ AT_DATA_GRAMMAR([[input.y]],
 start: { USE($$); } ;
 
 %%
-
-static int
-yylex (void)
-{
-  static int called;
-  if (called++)
-    abort ();
-  return 0;
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([])[
 int
 main (void)
 {
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input])
@@ -1189,14 +1099,15 @@ AT_CLEANUP
 
 AT_SETUP([Default %printer and %destructor for mid-rule values])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%debug /* So that %printer is actually compiled.  */
 
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (const char *msg);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 # define USE(SYM)
 # define YYLTYPE int
 # define YYLLOC_DEFAULT(Current, Rhs, N) (void)(Rhs)
@@ -1220,22 +1131,8 @@ start:
   ;
 
 %%
-
-static int
-yylex (void)
-{
-  static int called;
-  if (called++)
-    abort ();
-  return 0;
-}
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([])[
 int
 main (void)
 {
@@ -1243,6 +1140,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y], 0,,
 [[input.y:33.3-23: warning: unset value: $$
@@ -1296,15 +1194,15 @@ AT_CLEANUP
 # Bison once forgot to check for @$ in actions other than semantic actions.
 
 # AT_CHECK_ACTION_LOCATIONS(ACTION-DIRECTIVE)
-# -------------------------------------------------------
+# -------------------------------------------
 m4_define([AT_CHECK_ACTION_LOCATIONS],
 [AT_SETUP([[@$ in ]$1[ implies %locations]])
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%code {
   #include <stdio.h>
-  static int yylex (void);
-  static void yyerror (char const *msg);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 }
 
 %debug
@@ -1325,12 +1223,7 @@ yylex (void)
   return 0;
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
@@ -1340,7 +1233,7 @@ main (void)
 
 AT_BISON_CHECK([[-o input.c input.y]])
 AT_COMPILE([[input]])
-
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP])
 
 AT_CHECK_ACTION_LOCATIONS([[%initial-action]])
@@ -1357,7 +1250,7 @@ AT_SETUP([[Fix user actions without a trailing semicolon]])
 # This feature is undocumented, but we accidentally broke it in 2.3a,
 # and there was a complaint at:
 # <http://lists.gnu.org/archive/html/bug-bison/2008-11/msg00001.html>.
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA([input.y],
 [[%%
 start: test2 test1 test0 testc;
@@ -1407,6 +1300,7 @@ no_semi
 []"broken\" $ @ $$ @$ [];\
 string;"}
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o input.c input.y]], [0], [],
 [[input.y:8.48: warning: a ';' might be needed at the end of action code
@@ -1462,13 +1356,14 @@ AT_CLEANUP
 
 AT_SETUP([[Destroying lookahead assigned by semantic action]])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[
 %code {
   #include <assert.h>
   #include <stdio.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
   #define USE(Var)
 }
 
@@ -1496,27 +1391,15 @@ accept: /*empty*/ {
 } ;
 
 %%
-
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-static int
-yylex (void)
-{
-  static char const *input = "a";
-  return *input++;
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([a])[
 int
 main (void)
 {
   return yyparse ();
 }
 ]])
-
+AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-o input.c input.y]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[./input]], [[0]], [],
@@ -1532,6 +1415,8 @@ AT_CLEANUP
 
 AT_SETUP([[YYBACKUP]])
 
+AT_BISON_OPTION_PUSHDEFS([%pure-parser])
+
 AT_DATA_GRAMMAR([input.y],
 [[
 %error-verbose
@@ -1542,7 +1427,7 @@ AT_DATA_GRAMMAR([input.y],
 # include <stdlib.h>
 # include <assert.h>
 
-  static void yyerror (const char *msg);
+  ]AT_YYERROR_DECLARE[
   static int yylex (YYSTYPE *yylval);
 }
 %%
@@ -1557,6 +1442,7 @@ exp:
 ;
 
 %%
+]AT_YYERROR_DEFINE[
 static int
 yylex (YYSTYPE *yylval)
 {
@@ -1567,12 +1453,6 @@ yylex (YYSTYPE *yylval)
   return input[toknum++];
 }
 
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
 int
 main (void)
 {
@@ -1580,6 +1460,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o input.c input.y]])
 AT_COMPILE([[input]])
diff --git a/tests/calc.at b/tests/calc.at
index 477c92d3..5c6c4cc1 100644
--- a/tests/calc.at
+++ b/tests/calc.at
@@ -33,9 +33,80 @@
 # Don't call this macro directly, because it contains some occurrences
 # of `$1' etc. which will be interpreted by m4.  So you should call it
 # with $1, $2, and $3 as arguments, which is what AT_DATA_CALC_Y does.
+#
+# When %defines is not passed, generate a single self-contained file.
+# Otherwise, generate three: calc.y with the parser, calc-lex.c with
+# the scanner, and calc-main.c with "main()".  This is in order to
+# stress the use of the generated parser header.  To avoid code
+# duplication, AT_CALC_LEX and AT_CALC_MAIN contain the body of these
+# two later files.
 m4_define([_AT_DATA_CALC_Y],
 [m4_if([$1$2$3], $[1]$[2]$[3], [],
        [m4_fatal([$0: Invalid arguments: $@])])dnl
+
+m4_pushdef([AT_CALC_MAIN],
+[#include <stdlib.h> /* abort */
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else
+# undef alarm
+# define alarm(seconds) /* empty */
+#endif
+
+AT_SKEL_CC_IF([[
+/* A C++ ]AT_NAME_PREFIX[parse that simulates the C signature.  */
+int
+]AT_NAME_PREFIX[parse (]AT_PARAM_IF([semantic_value *result, int *count]))[
+{
+  ]AT_NAME_PREFIX[::parser parser]AT_PARAM_IF([ (result, count)])[;
+#if YYDEBUG
+  parser.set_debug_level (1);
+#endif
+  return parser.parse ();
+}
+]])[
+
+semantic_value global_result = 0;
+int global_count = 0;
+
+/* A C main function.  */
+int
+main (int argc, const char **argv)
+{
+  semantic_value result = 0;
+  int count = 0;
+  int status;
+
+  /* This used to be alarm (10), but that isn't enough time for
+     a July 1995 vintage DEC Alphastation 200 4/100 system,
+     according to Nelson H. F. Beebe.  100 seconds is enough.  */
+  alarm (100);
+
+  if (argc == 2)
+    input = fopen (argv[1], "r");
+  else
+    input = stdin;
+
+  if (!input)
+    {
+      perror (argv[1]);
+      return 3;
+    }
+
+]AT_SKEL_CC_IF([], [m4_bmatch([$4], [%debug],
+[  ]AT_NAME_PREFIX[debug = 1;])])[
+  status = ]AT_NAME_PREFIX[parse (]AT_PARAM_IF([[&result, &count]])[);
+  if (fclose (input))
+    perror ("fclose");
+  if (global_result != result)
+    abort ();
+  if (global_count != count)
+    abort ();
+  return status;
+}
+]])
+
+
 m4_pushdef([AT_CALC_LEX],
 [[#include <ctype.h>
 
@@ -198,7 +269,9 @@ AT_SKEL_CC_IF(
 {
 #include <stdio.h>
 /* The input.  */
-extern FILE *input;]AT_SKEL_CC_IF([[
+extern FILE *input;
+extern semantic_value global_result;
+extern int global_count;]AT_SKEL_CC_IF([[
 #ifndef YYLTYPE
 # define YYLTYPE ]AT_NAME_PREFIX[::parser::location_type
 #endif
@@ -208,19 +281,10 @@ extern FILE *input;]AT_SKEL_CC_IF([[
 %code
 {
 #include <assert.h>
-#include <stdlib.h>
 #include <string.h>
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#else
-# undef alarm
-# define alarm(seconds) /* empty */
-#endif
 #define USE(Var)
 
 FILE *input;
-static semantic_value global_result = 0;
-static int global_count = 0;
 static int power (int base, int exponent);
 
 ]AT_SKEL_CC_IF(,
@@ -289,6 +353,16 @@ exp:
 ;
 %%
 
+static int
+power (int base, int exponent)
+{
+  int res = 1;
+  assert (0 <= exponent);
+  for (/* Niente */; exponent; --exponent)
+    res *= base;
+  return res;
+}
+
 ]AT_SKEL_CC_IF(
 [AT_LOCATION_TYPE_IF([[
   std::ostream&
@@ -309,17 +383,6 @@ AT_NAME_PREFIX::parser::error (AT_LOCATION_IF([const location_type& l, ])const s
 {
   std::cerr << AT_LOCATION_IF([l << ": " << ])m << std::endl;
 }
-
-/* A C++ yyparse that simulates the C signature.  */
-int
-yyparse (AT_PARAM_IF([semantic_value *result, int *count]))
-{
-  AT_NAME_PREFIX::parser parser[]AT_PARAM_IF([ (result, count)]);
-#if YYDEBUG
-  parser.set_debug_level (1);
-#endif
-  return parser.parse ();
-}
 ],
 [/* A C error reporting function.  */
 static void
@@ -341,59 +404,21 @@ AT_YYERROR_SEES_LOC_IF([
   fprintf (stderr, "%s\n", s);
 }])[
 
-]AT_DEFINES_IF(, [AT_CALC_LEX])[
-
-static int
-power (int base, int exponent)
-{
-  int res = 1;
-  assert (0 <= exponent);
-  for (/* Niente */; exponent; --exponent)
-    res *= base;
-  return res;
-}
-
-
-/* A C main function.  */
-int
-main (int argc, const char **argv)
-{
-  semantic_value result = 0;
-  int count = 0;
-  int status;
-
-  /* This used to be alarm (10), but that isn't enough time for
-     a July 1995 vintage DEC Alphastation 200 4/100 system,
-     according to Nelson H. F. Beebe.  100 seconds is enough.  */
-  alarm (100);
-
-  if (argc == 2)
-    input = fopen (argv[1], "r");
-  else
-    input = stdin;
-
-  if (!input)
-    {
-      perror (argv[1]);
-      return 3;
-    }
-
-]AT_SKEL_CC_IF([], [m4_bmatch([$4], [%debug],
-[  yydebug = 1;])])[
-  status = yyparse (]AT_PARAM_IF([[&result, &count]])[);
-  if (fclose (input))
-    perror ("fclose");
-  if (global_result != result)
-    abort ();
-  if (global_count != count)
-    abort ();
-  return status;
-}
+]AT_DEFINES_IF([],
+[AT_CALC_LEX
+AT_CALC_MAIN])[
 ]])
+
 AT_DEFINES_IF([AT_DATA_SOURCE([[calc-lex.c]AT_SKEL_CC_IF([[c]])],
 [[#include "calc.h]AT_SKEL_CC_IF([[h]])["
 
-]AT_CALC_LEX])])
+]AT_CALC_LEX])
+AT_DATA_SOURCE([[calc-main.c]AT_SKEL_CC_IF([[c]])],
+[[#include "calc.h]AT_SKEL_CC_IF([[h]])["
+
+]AT_CALC_MAIN])
+])
+m4_popdef([AT_CALC_MAIN])
 m4_popdef([AT_CALC_LEX])
 ])# _AT_DATA_CALC_Y
 
@@ -506,7 +531,7 @@ m4_ifval([$2], [AT_CHECK([exit 77])])
 AT_BISON_OPTION_PUSHDEFS([$1])
 
 AT_DATA_CALC_Y([$1])
-AT_FULL_COMPILE([calc], [AT_DEFINES_IF([[lex]])])
+AT_FULL_COMPILE([calc], AT_DEFINES_IF([[lex], [main]]))
 
 # Test the priorities.
 _AT_CHECK_CALC([$1],
diff --git a/tests/conflicts.at b/tests/conflicts.at
index 599d708b..6c71a368 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -49,6 +49,7 @@ AT_CLEANUP
 
 AT_SETUP([%nonassoc and eof])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[
 %{
@@ -57,12 +58,7 @@ AT_DATA_GRAMMAR([input.y],
 #include <string.h>
 
 #define YYERROR_VERBOSE 1
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 /* The current argument. */
 static const char *input;
 
@@ -92,6 +88,7 @@ main (int argc, const char *argv[])
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 m4_pushdef([AT_NONASSOC_AND_EOF_CHECK],
 [AT_BISON_CHECK([$1[ -o input.c input.y]])
@@ -169,7 +166,7 @@ AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y],
   #include <string>]], [[
   #include <assert.h>
   #include <stdio.h>
-  void yyerror (char const *msg);]])[
+  ]AT_YYERROR_DECLARE])[
   ]AT_YYLEX_PROTOTYPE[;
   #define USE(Var)
 }
@@ -210,31 +207,11 @@ public Object getLVal ()
   *lvalp = 1;
   return *input++;
 }]])[
-
-/*----------.
-| yyerror.  |
-`----------*/]AT_SKEL_JAVA_IF([[
-
-public void yyerror (String msg)
-{
-  System.err.println (msg);
-}
-
+]AT_YYERROR_DEFINE[
+]AT_SKEL_JAVA_IF([[
 };
 
-%%]], [AT_SKEL_CC_IF([[
-
-void
-yy::parser::error (std::string const &msg)
-{
-  std::cerr << msg << std::endl;
-}]], [[
-
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}]])])[
+%%]])[
 
 /*-------.
 | main.  |
@@ -465,12 +442,12 @@ AT_CLEANUP
 # with minimal LR parser tables.
 
 AT_SETUP([[LAC: %nonassoc requires splitting canonical LR states]])
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([[input.y]],
 [[%code {
   #include <stdio.h>
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 }
 
 %error-verbose
@@ -507,19 +484,8 @@ look:
 reduce-nonassoc: %prec 'a';
 
 %%
-
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-int
-yylex (void)
-{
-  char const *input = "aaa";
-  return *input++;
-}
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([aaa])[
 
 int
 main (void)
@@ -527,6 +493,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 # Show canonical LR's failure.
 AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 4ac48611..67c60707 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -24,6 +24,7 @@ AT_BANNER([[GLR Regression Tests]])
 
 AT_SETUP([Badly Collapsed GLR States])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr1.y],
 [[/* Regression Test: Improper state compression */
 /* Reported by Scott McPeak */
@@ -34,8 +35,8 @@ AT_DATA_GRAMMAR([glr-regr1.y],
 
 #define YYSTYPE int
 static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
-int yylex (void);
-void yyerror (char const *msg);
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
 %}
 
 
@@ -71,12 +72,7 @@ main (void)
   return yyparse ();
 }
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 
 int
 yylex (void)
@@ -94,6 +90,7 @@ yylex (void)
     }
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr1.c glr-regr1.y]], 0, [],
 [glr-regr1.y: conflicts: 1 shift/reduce
@@ -119,6 +116,7 @@ AT_CLEANUP
 
 AT_SETUP([Improper handling of embedded actions and dollar(-N) in GLR parsers])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr2a.y],
 [[/* Regression Test: Improper handling of embedded actions and $-N  */
 /* Reported by S. Eken */
@@ -130,8 +128,8 @@ AT_DATA_GRAMMAR([glr-regr2a.y],
   #include <stdio.h>
   #include <stdlib.h>
   #include <string.h>
-  int yylex (void);
-  void yyerror (char const *);
+  ]AT_YYLEX_DECLARE[
+  ]AT_YYERROR_DECLARE[
 %}
 
 %glr-parser
@@ -171,7 +169,7 @@ var_printer: 'v'
    { printf ("Variable: '%s'\n", $-1); }
 
 %%
-
+]AT_YYERROR_DEFINE[
 FILE *input;
 
 int
@@ -181,7 +179,8 @@ yylex (void)
   char *s;
   if (feof (stdin))
     abort ();
-  switch (fscanf (input, " %1[a-z,]", buf)) {
+  switch (fscanf (input, " %1[a-z,]", buf))
+  {
   case 1:
     return buf[0];
   case EOF:
@@ -199,11 +198,6 @@ yylex (void)
   return 'V';
 }
 
-void
-yyerror (char const *s)
-{ printf ("%s\n", s);
-}
-
 int
 main (int argc, char **argv)
 {
@@ -212,6 +206,7 @@ main (int argc, char **argv)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr2a.c glr-regr2a.y]], 0, [],
 [glr-regr2a.y: conflicts: 2 shift/reduce
@@ -238,6 +233,7 @@ AT_CLEANUP
 
 AT_SETUP([Improper merging of GLR delayed action sets])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr3.y],
 [[/* Regression Test: Improper merging of GLR delayed action sets.  */
 /* Reported by M. Rosien */
@@ -248,8 +244,8 @@ AT_DATA_GRAMMAR([glr-regr3.y],
 #include <stdarg.h>
 
 static int MergeRule (int x0, int x1);
-static void yyerror (char const * s);
-int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 
 #define RULE(x) (1 << (x))
 
@@ -290,13 +286,12 @@ NT6 : P1 NT1 O1 T3 P2  { $$ = RULE(11) | $2; } %merge<MergeRule>
 
 %%
 
-static int MergeRule (int x0, int x1) {
+static int
+MergeRule (int x0, int x1)
+{
   return x0 | x1;
 }
-
-static void yyerror(char const * s) {
-  fprintf(stderr,"error: %s\n",s);
-}
+]AT_YYERROR_DEFINE[
 
 FILE *input = YY_NULL;
 
@@ -320,12 +315,15 @@ int yylex (void)
   return BAD_CHAR;
 }
 
-int main(int argc, char* argv[]) {
+int
+main(int argc, char* argv[])
+{
   input = stdin;
   if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr3.c glr-regr3.y]], 0, [],
 [glr-regr3.y: conflicts: 1 shift/reduce, 1 reduce/reduce
@@ -347,6 +345,7 @@ AT_CLEANUP
 
 AT_SETUP([Duplicate representation of merged trees])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr4.y],
 [[
 %union { char *ptr; }
@@ -359,8 +358,8 @@ AT_DATA_GRAMMAR([glr-regr4.y],
   #include <string.h>
   static char *merge (YYSTYPE, YYSTYPE);
   static char *make_value (char const *, char const *);
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static char *ptrs[100];
   static char **ptrs_next = ptrs;
 %}
@@ -384,16 +383,8 @@ A2: 'a' { $$ = make_value ("A2", "'a'"); } ;
 B:  'a' { $$ = make_value ("B", "'a'");  } ;
 
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "a";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([a])[
 
 int
 main (void)
@@ -423,13 +414,8 @@ merge (YYSTYPE s1, YYSTYPE s2)
   sprintf (value, format, s1.ptr, s2.ptr);
   return value;
 }
-
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr4.c glr-regr4.y]], 0, [],
 [glr-regr4.y: conflicts: 1 reduce/reduce
@@ -450,13 +436,14 @@ AT_CLEANUP
 
 AT_SETUP([User destructor for unresolved GLR semantic value])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr5.y],
 [[
 %{
   #include <stdio.h>
   #include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */
 %}
 
@@ -480,29 +467,15 @@ start:
    ;
 
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "a";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
-
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYLEX_DEFINE(a)[
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
   return yyparse () != 1;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr5.c glr-regr5.y]], 0, [],
 [glr-regr5.y: conflicts: 1 reduce/reduce
@@ -523,13 +496,14 @@ AT_CLEANUP
 
 AT_SETUP([User destructor after an error during a split parse])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr6.y],
 [[
 %{
   #include <stdio.h>
   #include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 %}
 
 %glr-parser
@@ -556,18 +530,14 @@ yylex (void)
   return input[toknum++];
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
   return yyparse () != 1;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr6.c glr-regr6.y]], 0, [],
 [glr-regr6.y: conflicts: 1 reduce/reduce
@@ -590,13 +560,14 @@ AT_CLEANUP
 
 AT_SETUP([Duplicated user destructor for lookahead])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr7.y],
 [[
 %{
   #include <stdio.h>
   #include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   #define YYSTACKEXPANDABLE 0
   typedef struct count_node {
     int count;
@@ -641,12 +612,7 @@ yylex (void)
   return 'a';
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
@@ -660,6 +626,7 @@ main (void)
   return status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr7.c glr-regr7.y]], 0, [],
 [glr-regr7.y: conflicts: 2 reduce/reduce
@@ -682,14 +649,15 @@ AT_CLEANUP
 
 AT_SETUP([Incorrectly initialized location for empty right-hand side in GLR])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr8.y],
 [[
 %{
   #include <stdio.h>
   #include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
-  static void yyerror (char const *msg);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
+  ]AT_YYERROR_DECLARE[
 %}
 
 %token T_CONSTANT
@@ -723,12 +691,7 @@ OptSignalWord   : /* empty */
 
 %%
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int lexIndex;
 
 int yylex (void)
@@ -758,6 +721,7 @@ main (void)
   return 0;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr8.c glr-regr8.y]], 0, [],
 [glr-regr8.y: conflicts: 1 reduce/reduce
@@ -780,13 +744,14 @@ AT_CLEANUP
 
 AT_SETUP([No users destructors if stack 0 deleted])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr9.y],
 [[
 %{
 # include <stdio.h>
 # include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 # define YYSTACKEXPANDABLE 0
   static int tokens = 0;
   static int destructors = 0;
@@ -822,12 +787,7 @@ yylex (void)
   return 'a';
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
@@ -841,6 +801,7 @@ main (void)
   return !exit_status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr9.c glr-regr9.y]], 0, [],
 [glr-regr9.y: conflicts: 1 reduce/reduce
@@ -860,13 +821,14 @@ AT_CLEANUP
 
 AT_SETUP([Corrupted semantic options if user action cuts parse])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr10.y],
 [[
 %{
 # include <stdlib.h>
 # include <stdio.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   #define GARBAGE_SIZE 50
   static char garbage[GARBAGE_SIZE];
 %}
@@ -884,12 +846,7 @@ start:
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -908,6 +865,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr10.c glr-regr10.y]], 0, [],
 [glr-regr10.y: conflicts: 1 reduce/reduce
@@ -925,12 +883,13 @@ AT_CLEANUP
 
 AT_SETUP([Undesirable destructors if user action cuts parse])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr11.y],
 [[
 %{
 # include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static int destructors = 0;
 # define USE(val)
 %}
@@ -949,21 +908,8 @@ start:
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-static int
-yylex (void)
-{
-  static char const input[] = "a";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([a])[
 
 int
 main (void)
@@ -977,6 +923,7 @@ main (void)
   return exit_status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr11.c glr-regr11.y]], 0, [],
 [glr-regr11.y: conflicts: 1 reduce/reduce
@@ -994,6 +941,7 @@ AT_CLEANUP
 
 AT_SETUP([Leaked semantic values if user action cuts parse])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr12.y],
 [[
 %glr-parser
@@ -1007,8 +955,8 @@ AT_DATA_GRAMMAR([glr-regr12.y],
 %{
 # include <stdlib.h>
   static int merge (YYSTYPE, YYSTYPE);
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static int parent_rhs_before_value = 0;
   static int merged_value = 0;
   static int parent_rhs_after_value = 0;
@@ -1068,12 +1016,7 @@ merge (YYSTYPE s1, YYSTYPE s2)
   return dummy;
 }
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1108,6 +1051,7 @@ main (void)
   return exit_status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr12.c glr-regr12.y]], 0, [],
 [glr-regr12.y: conflicts: 1 shift/reduce, 1 reduce/reduce
@@ -1127,6 +1071,7 @@ AT_CLEANUP
 
 AT_SETUP([Incorrect lookahead during deterministic GLR])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr13.y],
 [[
 /* Tests:
@@ -1138,8 +1083,8 @@ AT_DATA_GRAMMAR([glr-regr13.y],
 
 %{
   #include <stdio.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static void print_lookahead (char const *);
   #define USE(value)
 %}
@@ -1190,12 +1135,7 @@ change_lookahead:
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1237,6 +1177,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr13.c glr-regr13.y]], 0, [], [])
 AT_COMPILE([glr-regr13])
@@ -1263,6 +1204,7 @@ AT_CLEANUP
 
 AT_SETUP([Incorrect lookahead during nondeterministic GLR])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr14.y],
 [[
 /* Tests:
@@ -1289,8 +1231,8 @@ AT_DATA_GRAMMAR([glr-regr14.y],
 %{
   #include <stdlib.h>
   #include <stdio.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static void print_lookahead (char const *);
   static char merge (union YYSTYPE, union YYSTYPE);
   #define USE(value)
@@ -1399,12 +1341,7 @@ no_look:
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1453,6 +1390,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr14.c glr-regr14.y]], 0, [],
 [glr-regr14.y: conflicts: 3 reduce/reduce
@@ -1483,6 +1421,7 @@ AT_CLEANUP
 
 AT_SETUP([Leaked semantic values when reporting ambiguity])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr15.y],
 [[
 %glr-parser
@@ -1490,8 +1429,8 @@ AT_DATA_GRAMMAR([glr-regr15.y],
 
 %{
 # include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static int parent_rhs_before_value = 0;
 # define USE(val)
 %}
@@ -1530,12 +1469,7 @@ ambiguity2: ;
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1557,6 +1491,7 @@ main (void)
   return exit_status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr15.c glr-regr15.y]], 0, [],
 [glr-regr15.y: conflicts: 2 reduce/reduce
@@ -1575,6 +1510,8 @@ AT_CLEANUP
 ## ------------------------------------------------------------------------- ##
 
 AT_SETUP([Leaked lookahead after nondeterministic parse syntax error])
+
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr16.y],
 [[
 %glr-parser
@@ -1582,8 +1519,8 @@ AT_DATA_GRAMMAR([glr-regr16.y],
 
 %{
 # include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   static int lookahead_value = 0;
 # define USE(val)
 %}
@@ -1596,12 +1533,7 @@ alt2: ;
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1626,6 +1558,7 @@ main (void)
   return exit_status;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr16.c glr-regr16.y]], 0, [],
 [glr-regr16.y: conflicts: 1 reduce/reduce
@@ -1644,6 +1577,8 @@ AT_CLEANUP
 ## ------------------------------------------------------------------------- ##
 
 AT_SETUP([Uninitialized location when reporting ambiguity])
+
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr17.y],
 [[
 %glr-parser
@@ -1713,6 +1648,7 @@ main (void)
   return yyparse () != 1;
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr17.c glr-regr17.y]], 0, [],
 [glr-regr17.y: conflicts: 3 reduce/reduce
@@ -1731,12 +1667,14 @@ AT_CLEANUP
 ## -------------------------------------------------------------##
 
 AT_SETUP([Missed %merge type warnings when LHS type is declared later])
+
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr18.y],
 [[%glr-parser
 
 %{
   #include <stdlib.h>
-  static void yyerror (char const *);
+  ]AT_YYERROR_DECLARE[
   static int yylex ();
 %}
 
@@ -1758,27 +1696,15 @@ sym3: %merge<merge> { $$ = 0; } ;
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-static int
-yylex ()
-{
-  static int called;
-  if (called++)
-    abort ();
-  return 0;
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE()[
 int
 main (void)
 {
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr18.c glr-regr18.y]], 1, [],
 [glr-regr18.y:26.18-24: result type clash on merge function 'merge': <type2> != <type1>
@@ -1796,13 +1722,14 @@ AT_CLEANUP
 
 AT_SETUP([Ambiguity reports])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[
 %{
   #include <stdio.h>
   #include <stdlib.h>
-  static void yyerror (char const *);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 %}
 
 %debug
@@ -1816,23 +1743,8 @@ start:
 b: 'b';
 d: /* nada.  */;
 %%
-
-static int
-yylex (void)
-{
-  static char const input[] = "abc";
-  static size_t toknum;
-  if (! (toknum < sizeof input))
-    abort ();
-  return input[toknum++];
-}
-
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYLEX_DEFINE([abc])[
+]AT_YYERROR_DEFINE[
 int
 main (void)
 {
@@ -1840,6 +1752,7 @@ main (void)
   return !!yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o input.c input.y]], 0, [],
 [input.y: conflicts: 1 reduce/reduce
diff --git a/tests/headers.at b/tests/headers.at
index 9d4946d6..a28f2e1b 100644
--- a/tests/headers.at
+++ b/tests/headers.at
@@ -19,47 +19,26 @@
 AT_BANNER([[Parser Headers.]])
 
 
-## ---------------------- ##
-## %union and --defines.  ##
-## ---------------------- ##
-
-
-AT_SETUP([%union and --defines])
-
-AT_DATA([input.y],
-[%union
-{
-  int   integer;
-  char *string ;
-}
-%%
-exp: {};
-])
-
-AT_BISON_CHECK([--defines input.y])
-
-AT_CLEANUP
-
-
-
 ## --------------------- ##
 ## Invalid CPP headers.  ##
 ## --------------------- ##
 
-# AT_TEST_CPP_GUARD_H([INPUT-FILE-BASE)
-# -------------------------------------
+# AT_TEST_CPP_GUARD_H(BASE-NAME, [DIRECTIVES])
+# --------------------------------------------
+# FIXME: Much of this can be covered by calc.at.
 m4_define([AT_TEST_CPP_GUARD_H],
-[AT_SETUP([Invalid CPP guards: $1])
-
+[AT_SETUP([Invalid CPP guards: $2 --defines=$1.h])
+AT_BISON_OPTION_PUSHDEFS([$2])
 # Possibly create inner directories.
 dirname=`AS_DIRNAME([$1])`
 AS_MKDIR_P([$dirname])
 
 AT_DATA_GRAMMAR([$1.y],
-[%{
+[$2
+%{
 #include <$1.h>
-void yyerror (const char *);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %%
 dummy:;
@@ -67,15 +46,18 @@ dummy:;
 #include <$1.h>
 ])
 
-AT_BISON_CHECK([--defines=$1.h --output=y.tab.c $1.y])
+AT_BISON_CHECK([--defines=$1.h --output=$1.c $1.y])
 
-AT_COMPILE([y.tab.o], [-I. -c y.tab.c])
+AT_COMPILE([$1.o], [-I. -c $1.c])
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
 AT_TEST_CPP_GUARD_H([input/input])
 AT_TEST_CPP_GUARD_H([9foo])
+AT_TEST_CPP_GUARD_H([input/input], [%glr-parser])
+AT_TEST_CPP_GUARD_H([9foo],        [%glr-parser])
 
 
 
diff --git a/tests/input.at b/tests/input.at
index d0bc51a7..d94b652e 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -386,7 +386,7 @@ AT_CLEANUP
 
 AT_SETUP([Torturing the Scanner])
 
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA([input.y], [])
 AT_BISON_CHECK([input.y], [1], [],
 [[input.y:1.1: syntax error, unexpected end of file
@@ -463,8 +463,8 @@ char quote[] = "@:>@@:>@,";
 %}
 
 %{
-static void yyerror (const char *s);
-static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 
 %type <ival> '@<:@'
@@ -496,7 +496,7 @@ value_as_yystype (value val)
   res.ival = val;
   return res;
 }
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -509,12 +509,6 @@ yylex (void)
   yylval = value_as_yystype (input[toknum]);
   return input[toknum++];
 }
-
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
 ]])
 
 # Pacify Emacs'font-lock-mode: "
@@ -531,6 +525,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-d -v -o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -616,14 +611,15 @@ AT_CLEANUP
 
 AT_SETUP([Symbols])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%token WITH-DASH
 %token WITHOUT_DASH "WITHOUT-DASH"
 %token WITH.PERIOD
 %token WITHOUT_PERIOD "WITHOUT.PERIOD"
 %code {
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 }
 %%
 start: with-dash without_dash with.period without_period;
@@ -632,7 +628,10 @@ without_dash: "WITHOUT-DASH";
 with.period: WITH.PERIOD;
 without_period: "WITHOUT.PERIOD";
 %%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE[
 ]])
+AT_BISON_OPTION_POPDEFS
 
 # POSIX Yacc accept periods, but not dashes.
 AT_BISON_CHECK([--yacc input.y], [1], [],
diff --git a/tests/local.at b/tests/local.at
index a53f1d17..0d24a44a 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -109,7 +109,7 @@ m4_pushdef([AT_SKEL_CC_IF],
 m4_pushdef([AT_SKEL_JAVA_IF],
 [m4_bmatch([$3], [%language "[Jj][Aa][Vv][Aa]"\|%skeleton "[a-z0-9]+\.java"], [$1], [$2])])
 m4_pushdef([AT_GLR_IF],
-[m4_bmatch([$3], [%glr-parser\|%skeleton "glr\.], [$1], [$2])])
+[m4_bmatch([$3], [%glr-parser\|%skeleton "glr\..*"], [$1], [$2])])
 m4_pushdef([AT_LALR1_CC_IF],
 [AT_SKEL_CC_IF([AT_GLR_IF([$2], [$1])], [$2])])
 m4_pushdef([AT_GLR_CC_IF],
@@ -135,7 +135,11 @@ m4_pushdef([AT_GLR_OR_PARAM_IF],
 [m4_bmatch([$3], [%glr-parser\|%parse-param], [$1], [$2])])
 m4_pushdef([AT_NAME_PREFIX],
 [m4_bmatch([$3], [%name-prefix ".*"],
-           [m4_bregexp([$3], [name-prefix "\([^"]*\)"], [\1])],
+           [m4_bregexp([$3], [name-prefix "\([^""]*\)"], [\1])],
+           [yy])])
+m4_pushdef([AT_API_PREFIX],
+[m4_bmatch([$3], [%define api\.prefix ".*"],
+           [m4_bregexp([$3], [%define api\.prefix "\([^""]*\)"], [\1])],
            [yy])])
 m4_pushdef([AT_TOKEN_PREFIX],
 [m4_bmatch([$3], [%define api.tokens.prefix ".*"],
@@ -207,6 +211,7 @@ m4_popdef([AT_LOC])
 m4_popdef([AT_PURE_LEX_IF])
 m4_popdef([AT_YYERROR_SEES_LOC_IF])
 m4_popdef([AT_YYERROR_ARG_LOC_IF])
+m4_popdef([AT_API_PREFIX])
 m4_popdef([AT_NAME_PREFIX])
 m4_popdef([AT_GLR_OR_PARAM_IF])
 m4_popdef([AT_PURE_AND_LOC_IF])
@@ -272,6 +277,70 @@ m4_define([AT_DATA_GRAMMAR],
 $2])
 ])
 
+# AT_YYLEX_DECLARE_EXTERN
+# AT_YYLEX_DECLARE
+# AT_YYLEX_DEFINE(INPUT-STRING, [ACTION])
+# ---------------------------------------
+m4_define([AT_YYLEX_DECLARE_EXTERN],
+[int AT_API_PREFIX[]lex (void);dnl
+])
+
+m4_define([AT_YYLEX_DECLARE],
+[static AT_YYLEX_DECLARE_EXTERN[]dnl
+])
+
+m4_define([AT_YYLEX_DEFINE],
+[[#include <stdlib.h> /* abort */
+static int
+]AT_API_PREFIX[lex (void)
+{
+  static char const input[] = "$1";
+  static size_t toknum = 0;
+  int res;
+  if (! (toknum < sizeof input))
+    abort ();
+  res = input[toknum++];
+  ]$2;[]AT_LOCATION_IF([[
+  ]AT_API_PREFIX[lloc.first_line = ]AT_API_PREFIX[lloc.last_line = 1;
+  ]AT_API_PREFIX[lloc.first_column = ]AT_API_PREFIX[lloc.last_column = toknum;]])[
+  return res;
+}]dnl
+])
+
+# AT_YYERROR_DECLARE_EXTERN
+# AT_YYERROR_DECLARE
+# AT_YYERROR_DEFINE
+# -------------------------
+# Beware that must be called inside a AT_BISON_OPTION_PUSHDEFS/POPDEFS
+# pair.
+m4_define([AT_YYERROR_DECLARE_EXTERN],
+[void AT_API_PREFIX[]error (const char *msg);dnl
+])
+
+m4_define([AT_YYERROR_DECLARE],
+[static AT_YYERROR_DECLARE_EXTERN[]dnl
+])
+
+m4_define([AT_YYERROR_DEFINE],
+[AT_SKEL_JAVA_IF([[public void yyerror (String msg)
+{
+  System.err.println (msg);
+}]], [AT_SKEL_CC_IF([[void
+yy::parser::error (const yy::location &, std::string const &msg)
+{
+  std::cerr << msg << std::endl;
+}]], [[#include <stdio.h>
+static void
+]AT_API_PREFIX[error (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}]])])dnl
+])
+
+## --------------- ##
+## Running Bison.  ##
+## --------------- ##
+
 # AT_BISON_CHECK(BISON_ARGS, [OTHER_AT_CHECK_ARGS])
 # -------------------------------------------------
 # Check Bison by invoking `bison BISON_ARGS'.  BISON_ARGS should not contain
@@ -455,8 +524,8 @@ AT_CHECK([[test -n "$CONF_JAVA" || exit 77
 AT_CHECK([[$SHELL ../../../javacomp.sh ]$1],
          [[0]], [ignore], [ignore])])
 
-# AT_FULL_COMPILE(OUTPUT, [OTHER])
-# --------------------------------
+# AT_FULL_COMPILE(OUTPUT, [OTHER1], [OTHER2])
+# -------------------------------------------
 # Compile OUTPUT.y to OUTPUT.c, OUTPUT.cc, or OUTPUT.java, and then
 # compile it to OUTPUT or OUTPUT.class.  If OTHER is specified, compile
 # OUTPUT-OTHER.c, OUTPUT-OTHER.cc, or OUTPUT-OTHER.java to OUTPUT or
@@ -464,16 +533,27 @@ AT_CHECK([[$SHELL ../../../javacomp.sh ]$1],
 # AT_SKEL_JAVA_IF.
 m4_define([AT_FULL_COMPILE], [
   AT_SKEL_JAVA_IF([
-    AT_BISON_CHECK([[-o ]$1[.java ]$1[.y]])
-    AT_JAVA_COMPILE([$1[.java]]m4_ifval($2,
-                                        [[$1[.java ]$1[-]$2[.java]]]))
+    AT_BISON_CHECK([-o $1.java $1.y])
+    AT_JAVA_COMPILE([$1.java],
+                    m4_join([ ],
+                            [$1.java],
+                            m4_ifval($2, [[$1-$2.java]]),
+                            m4_ifval($3, [[$1-$3.java]])))
   ], [
     AT_SKEL_CC_IF([
-      AT_BISON_CHECK([[-o ]$1[.cc ]$1[.y]])
-      AT_COMPILE_CXX([$1]m4_ifval($2, [, [$1[.cc ]$1[-]$2[.cc]]]))
+      AT_BISON_CHECK([-o $1.cc $1.y])
+      AT_COMPILE_CXX([$1],
+                     m4_join([ ],
+                             [$1.cc],
+                             m4_ifval($2, [[$1-$2.cc]]),
+                             m4_ifval($3, [[$1-$3.cc]])))
     ], [
-      AT_BISON_CHECK([[-o ]$1[.c ]$1[.y]])
-      AT_COMPILE([$1]m4_ifval($2, [, [$1[.c ]$1[-]$2[.c]]]))
+      AT_BISON_CHECK([-o $1.c $1.y])
+      AT_COMPILE([$1],
+                  m4_join([ ],
+                          [$1.c],
+                          m4_ifval($2, [[$1-$2.c]]),
+                          m4_ifval($3, [[$1-$3.c]])))
     ])
   ])
 ])
@@ -582,12 +662,12 @@ m4_define([AT_TEST_TABLES_AND_PARSE],
 [m4_pushdef([AT_COND_CASE], [m4_case([$2], $][@)])
 
 AT_SETUP([$1])
-
+AT_BISON_OPTION_PUSHDEFS([$4])
 AT_DATA_GRAMMAR([[input.y]],
 [[%code {
   #include <stdio.h>
-  static void yyerror (char const *msg);
-  static int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 }
 
 ]$4[
@@ -597,13 +677,7 @@ AT_DATA_GRAMMAR([[input.y]],
 ]$5[
 
 %%
-
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -659,6 +733,7 @@ AT_PARSER_CHECK([[./input]],
                 m4_ifval([$11], [m4_dquote($11)]),
                 m4_ifval([$12], [m4_dquote($12)]))
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 m4_popdef([AT_COND_CASE])])
diff --git a/tests/named-refs.at b/tests/named-refs.at
index 0b2f4c94..0e6f60c8 100644
--- a/tests/named-refs.at
+++ b/tests/named-refs.at
@@ -19,7 +19,7 @@
 AT_BANNER([[Named references tests.]])
 
 AT_SETUP([Tutorial calculator])
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([test.y],
 [[
 %{
@@ -33,8 +33,8 @@ FILE *input;
 static semantic_value global_result = 0;
 static int global_count = 0;
 static int power (int base, int exponent);
-static void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 
 %union
@@ -83,12 +83,7 @@ exp:
 | '-' error          { $$ = 0; YYERROR;     }
 ;
 %%
-
-static void yyerror (const char *s)
-{
-  fprintf (stderr, "%s\n", s);
-}
-
+]AT_YYERROR_DEFINE[
 static int get_char (void)
 {
   int res = getc (input);
@@ -119,7 +114,8 @@ static int read_signed_integer (void)
   return sign * n;
 }
 
-int yylex (void)
+static int
+yylex (void)
 {
   int c;
   /* Skip white space.  */
@@ -190,6 +186,7 @@ AT_DATA([input.txt],
 AT_BISON_CHECK([-o test.c test.y])
 AT_COMPILE([[test]])
 AT_PARSER_CHECK([./test input.txt], 0, [], [stderr])
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
@@ -198,13 +195,13 @@ AT_CLEANUP
 
 
 AT_SETUP([Undefined and ambiguous references])
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([test.y],
 [[
 %{
 static int power (int base, int exponent);
-static void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 
 %union
@@ -268,6 +265,7 @@ test.y:55.3-53:      symbol not found in production: r12
 test.y:56.29-33: invalid reference: '$expo'
 test.y:56.3-46:      symbol not found in production: expo
 ]])
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 #######################################################################
diff --git a/tests/regression.at b/tests/regression.at
index ff798a87..fd08800a 100644
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -24,10 +24,11 @@ AT_BANNER([[Regression tests.]])
 
 AT_SETUP([Trivial grammars])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
-void yyerror (char const *);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 #define YYSTYPE int *
 %}
 
@@ -37,6 +38,7 @@ int yylex (void);
 
 program: 'x';
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -52,10 +54,11 @@ AT_CLEANUP
 
 AT_SETUP([YYSTYPE typedef])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
-void yyerror (char const *);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 typedef union { char const *val; } YYSTYPE;
 %}
 
@@ -65,6 +68,7 @@ typedef union { char const *val; } YYSTYPE;
 
 program: { $$ = ""; };
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -83,10 +87,11 @@ AT_SETUP([Early token definitions with --yacc])
 # Found in GCJ: they expect the tokens to be defined before the user
 # prologue, so that they can use the token definitions in it.
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 
 %union
@@ -103,6 +108,7 @@ int yylex (void);
 exp: MY_TOKEN;
 %%
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-y -o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -121,11 +127,12 @@ AT_SETUP([Early token definitions without --yacc])
 # Found in GCJ: they expect the tokens to be defined before the user
 # prologue, so that they can use the token definitions in it.
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
 #include <stdio.h>
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 void print_my_token (void);
 %}
 
@@ -146,6 +153,7 @@ print_my_token (void)
 exp: MY_TOKEN;
 %%
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -161,6 +169,7 @@ AT_CLEANUP
 
 AT_SETUP([Braces parsing])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA([input.y],
 [[/* Bison used to swallow the character after '}'. */
 
@@ -168,6 +177,7 @@ AT_DATA([input.y],
 exp: { tests = {{{{{{{{{{}}}}}}}}}}; };
 %%
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-v -o input.c input.y])
 
@@ -183,6 +193,7 @@ AT_CLEANUP
 
 AT_SETUP([Duplicate string])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA([input.y],
 [[/* 'Bison -v' used to dump core when two tokens are defined with the same
    string, as LE and GE below. */
@@ -195,6 +206,7 @@ AT_DATA([input.y],
 exp: '(' exp ')' | NUM ;
 %%
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-v -o input.c input.y], 0, [],
 [[input.y:6.8-14: warning: symbol "<=" used more than once as a literal string
@@ -211,6 +223,7 @@ AT_SETUP([Rule Line Numbers])
 
 AT_KEYWORDS([report])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA([input.y],
 [[%%
 expr:
@@ -240,6 +253,7 @@ expr:
 
 };
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c -v input.y])
 
@@ -428,13 +442,14 @@ AT_CLEANUP
 
 AT_SETUP([Token definitions])
 
+AT_BISON_OPTION_PUSHDEFS
 # Bison managed, when fed with '%token 'f' "f"' to #define 'f'!
 AT_DATA_GRAMMAR([input.y],
 [%{
 #include <stdlib.h>
 #include <stdio.h>
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 [%error-verbose
 %token MYEOF 0 "end of file"
@@ -468,6 +483,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 # Checking the warning message guarantees that the trigraph "??!" isn't
 # unnecessarily escaped here even though it would need to be if encoded in a
@@ -498,19 +514,21 @@ AT_CLEANUP
 
 AT_SETUP([Characters Escapes])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [%{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 [%%
 exp:
   '\'' "\'"
 | '\"' "\""
-| '"'  "'"
+| '"'  "'" /* Pacify font-lock-mode: ". */
 ;
 ]])
-# Pacify font-lock-mode: "
+
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input.o], [-c input.c])
@@ -828,7 +846,7 @@ static int yylex (AT_LALR1_CC_IF([int *], [void]));
 AT_LALR1_CC_IF([#include <cstdlib>],
 [#include <stdlib.h>
 #include <stdio.h>
-static void yyerror (const char *);])
+]AT_YYERROR_DECLARE[])
 %}
 $1
 %token ARROW INVALID NUMBER STRING DATA
@@ -953,10 +971,10 @@ m4_define([_AT_DATA_EXPECT2_Y],
 [AT_DATA_GRAMMAR([expect2.y],
 [%{
 static int yylex (AT_LALR1_CC_IF([int *], [void]));
-AT_LALR1_CC_IF([#include <cstdlib>],
-[#include <stdio.h>
-#include <stdlib.h>
-static void yyerror (const char *);])
+AT_LALR1_CC_IF([[#include <cstdlib>]],
+[[#include <stdlib.h>
+#include <stdio.h>
+]AT_YYERROR_DECLARE])[
 %}
 $1
 %defines
@@ -973,30 +991,19 @@ e: e '+' t | t;
 t: A | B;
 
 %%
-AT_LALR1_CC_IF(
-[/* A C++ error reporting function. */
-void
-yy::parser::error (const std::string& m)
-{
-  std::cerr << m << std::endl;
-}
-
-int
+]AT_YYERROR_DEFINE[
+]AT_LALR1_CC_IF(
+[int
 yyparse ()
 {
   yy::parser parser;
   return parser.parse ();
 }
-],
-[static void
-yyerror (const char *s)
-{
-  fprintf (stderr, "%s\n", s);
-}])
+])[
 
 static int
-yylex (AT_LALR1_CC_IF([int *lval], [void]))
-[{
+yylex (]AT_LALR1_CC_IF([int *lval], [void])[)
+{
   static int const tokens[] =
     {
       1000, '+', '+', -1
@@ -1006,19 +1013,19 @@ yylex (AT_LALR1_CC_IF([int *lval], [void]))
   if (! (toknum < sizeof tokens / sizeof *tokens))
     abort ();
   return tokens[toknum++];
-}]
+}
 
 int
 main (void)
 {
   return yyparse ();
 }
-])
+]])
 ])# _AT_DATA_EXPECT2_Y
 
 
 # AT_CHECK_EXPECT2(BISON-OPTIONS)
-# ------------------------------
+# -------------------------------
 # Generate the grammar, compile it, run it.
 m4_define([AT_CHECK_EXPECT2],
 [AT_SETUP([Expecting two tokens $1])
@@ -1047,12 +1054,12 @@ AT_SETUP([Braced code in declaration in rules section])
 
 # Bison once mistook braced code in a declaration in the rules section to be a
 # rule action.
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
 #include <stdio.h>
-static void yyerror (char const *msg);
-static int yylex (void);
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
 %}
 
 %error-verbose
@@ -1071,12 +1078,7 @@ start:
 
 %%
 
-static void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -1090,6 +1092,7 @@ main (void)
   return !yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([-t -o input.c input.y])
 AT_COMPILE([input])
@@ -1187,12 +1190,12 @@ AT_SETUP([[Token number in precedence declaration]])
 
 # POSIX says token numbers can be declared in %left, %right, and %nonassoc, but
 # we lost this in Bison 1.50.
-
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%{
   #include <stdio.h>
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 %}
 
 %error-verbose
@@ -1212,12 +1215,7 @@ sr_conflict:
 
 %%
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 yylex (void)
 {
@@ -1232,6 +1230,7 @@ main (void)
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o input.c input.y]], [[0]],,
 [[input.y:23.5-19: warning: rule useless in parser due to conflicts: start: start
@@ -1275,11 +1274,12 @@ AT_CLEANUP
 
 AT_SETUP([[parse.error=verbose and YYSTACK_USE_ALLOCA]])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%code {
   #include <stdio.h>
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   #define YYSTACK_USE_ALLOCA 1
 }
 
@@ -1315,28 +1315,18 @@ syntax_error:
 
 %%
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-int
-yylex (void)
-{
+]AT_YYERROR_DEFINE[
   /* Induce two syntax error messages (which requires full error
      recovery by shifting 3 tokens) in order to detect any loss of the
      reallocated buffer.  */
-  static char const *input = "abc";
-  return *input++;
-}
-
+]AT_YYLEX_DEFINE([abc])[
 int
 main (void)
 {
   return yyparse ();
 }
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o input.c input.y]])
 AT_COMPILE([[input]])
@@ -1363,11 +1353,12 @@ AT_CLEANUP
 
 AT_SETUP([[parse.error=verbose overflow]])
 
+AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%code {
   #include <stdio.h>
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
 
   /* This prevents this test case from having to induce error messages
      large enough to overflow size_t.  */
@@ -1433,21 +1424,10 @@ syntax_error2:
 
 %%
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-int
-yylex (void)
-{
+]AT_YYERROR_DEFINE[
   /* Induce two syntax error messages (which requires full error
      recovery by shifting 3 tokens).  */
-  static char const *input = "abc";
-  return *input++;
-}
-
+]AT_YYLEX_DEFINE([abc])[
 int
 main (void)
 {
@@ -1473,7 +1453,7 @@ AT_PARSER_CHECK([[./input]], [[2]], [],
 syntax error
 memory exhausted
 ]])
-
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
@@ -1491,7 +1471,7 @@ AT_BISON_OPTION_PUSHDEFS([$1])
 AT_DATA_GRAMMAR([input.y],
 [[%code {
   #include <stdio.h>
-  void yyerror (char const *);
+  ]AT_YYERROR_DECLARE[
   int yylex (]AT_PURE_IF([[YYSTYPE *]], [[void]])[);
 }
 
@@ -1512,13 +1492,7 @@ B: 'b' ;
 C: /*empty*/ { printf ("consistent default reduction\n"); } ;
 
 %%
-
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 yylex (]AT_PURE_IF([[YYSTYPE *v]], [[void]])[)
 {
@@ -1584,13 +1558,13 @@ AT_CLEANUP
 
 AT_SETUP([[LAC: Memory exhaustion]])
 
-m4_pushdef([AT_LAC_CHECK], [
-
+m4_pushdef([AT_LAC_CHECK],
+[AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([input.y],
 [[%code {
   #include <stdio.h>
-  void yyerror (char const *);
-  int yylex (void);
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
   #define YYMAXDEPTH 8
 }
 
@@ -1602,20 +1576,8 @@ S: A A A A A A A A A ;
 A: /*empty*/ | 'a' ;
 
 %%
-
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
-int
-yylex (void)
-{
-  static char const *input = "]$1[";
-  return *input++;
-}
-
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([$1])[
 int
 main (void)
 {
@@ -1629,12 +1591,12 @@ AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity-initial=1 \
 [[input.y: conflicts: 8 shift/reduce
 ]])
 AT_COMPILE([[input]])
-
+AT_BISON_OPTION_POPDEFS
 ])
 
 # Check for memory exhaustion during parsing.
-AT_LAC_CHECK([[]])
-AT_PARSER_CHECK([[./input]], [[2]], [[]],
+AT_LAC_CHECK([])
+AT_PARSER_CHECK([[./input]], [[2]], [],
 [[Starting parse
 Entering state 0
 Reading a token: Now at end of input.
@@ -1647,8 +1609,8 @@ Stack now 0
 
 # Induce an immediate syntax error with an undefined token, and check
 # for memory exhaustion while building syntax error message.
-AT_LAC_CHECK([[z]], [[0]])
-AT_PARSER_CHECK([[./input]], [[2]], [[]],
+AT_LAC_CHECK([z], [[0]])
+AT_PARSER_CHECK([[./input]], [[2]], [],
 [[Starting parse
 Entering state 0
 Reading a token: Next token is token $undefined ()
diff --git a/tests/skeletons.at b/tests/skeletons.at
index 1a9933fe..76cf0662 100644
--- a/tests/skeletons.at
+++ b/tests/skeletons.at
@@ -83,10 +83,11 @@ AT_CLEANUP
 
 AT_SETUP([[Installed skeleton file names]])
 
+AT_BISON_OPTION_PUSHDEFS
 m4_pushdef([AT_GRAM],
 [[%{
   #include <stdio.h>
-  void yyerror (char const *msg);
+  ]AT_YYERROR_DECLARE[
   int yylex (void);
 %}
 
@@ -99,12 +100,7 @@ start: ;
 
 %%
 
-void
-yyerror (char const *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 int
 yylex (void)
 {
@@ -139,6 +135,7 @@ AT_PARSER_CHECK([[./input-gram]], [[1]], [],
 
 m4_popdef([AT_GRAM])
 
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 
 
diff --git a/tests/synclines.at b/tests/synclines.at
index c12ab9b7..8d742d53 100644
--- a/tests/synclines.at
+++ b/tests/synclines.at
@@ -68,7 +68,7 @@ AT_CHECK([[sed -e '/^distcc\[[0-9]*\] /d'                            \
 # to issue ERROR-MSG.
 m4_define([AT_TEST_SYNCLINE],
 [AT_SETUP([$1])
-
+AT_BISON_OPTION_PUSHDEFS
 # It seems impossible to find a generic scheme to check the location
 # of an error.  Even requiring GCC is not sufficient, since for instance
 # the version modified by Apple:
@@ -98,6 +98,7 @@ AT_DATA([[input.y]], [$2])
 AT_BISON_CHECK([-o input.c input.y])
 AT_SYNCLINES_COMPILE([input.c])
 AT_CHECK([cat stdout], 0, [$3])
+AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
@@ -110,11 +111,12 @@ AT_CLEANUP
 AT_TEST_SYNCLINE([Prologue synch line],
 [[%{
 #error "2"
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %%
 exp: '0';
+%%
 ]],
 [input.y:2: #error "2"
 ])
@@ -130,11 +132,12 @@ AT_TEST_SYNCLINE([%union synch line],
   char dummy;
 }
 %{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %%
 exp: '0';
+%%
 ]],
 [input.y:2: #error "2"
 ])
@@ -146,8 +149,8 @@ exp: '0';
 
 AT_TEST_SYNCLINE([Postprologue synch line],
 [[%{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %union
 {
@@ -158,6 +161,7 @@ int yylex (void);
 %}
 %%
 exp: '0';
+%%
 ]],
 [input.y:10: #error "10"
 ])
@@ -169,8 +173,8 @@ exp: '0';
 
 AT_TEST_SYNCLINE([Action synch line],
 [[%{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %%
 exp:
@@ -188,8 +192,8 @@ exp:
 
 AT_TEST_SYNCLINE([Epilogue synch line],
 [[%{
-void yyerror (const char *s);
-int yylex (void);
+]AT_YYERROR_DECLARE_EXTERN[
+]AT_YYLEX_DECLARE_EXTERN[
 %}
 %%
 exp: '0';
diff --git a/tests/torture.at b/tests/torture.at
index 253041e6..061467d0 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -42,7 +42,8 @@ esac])
 # Create FILE-NAME, containing a self checking parser for a huge
 # triangular grammar.
 m4_define([AT_DATA_TRIANGULAR_GRAMMAR],
-[AT_DATA([[gengram.pl]],
+[AT_BISON_OPTION_PUSHDEFS
+AT_DATA([[gengram.pl]],
 [[#! /usr/bin/perl -w
 
 use strict;
@@ -56,8 +57,8 @@ print <<EOF;
 #include <stdio.h>
 #include <stdlib.h>
 
-static int yylex (void);
-static void yyerror (const char *msg);
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
 %}
 %union
 {
@@ -127,6 +128,7 @@ main (void)
 }
 EOF
 ]])
+AT_BISON_OPTION_POPDEFS
 
 AT_CHECK([perl -w ./gengram.pl $2 || exit 77], 0, [stdout])
 mv stdout $1
@@ -157,7 +159,8 @@ AT_CLEANUP
 # Create FILE-NAME, containing a self checking parser for a huge
 # horizontal grammar.
 m4_define([AT_DATA_HORIZONTAL_GRAMMAR],
-[AT_DATA([[gengram.pl]],
+[AT_BISON_OPTION_PUSHDEFS
+AT_DATA([[gengram.pl]],
 [[#! /usr/bin/perl -w
 
 use strict;
@@ -171,8 +174,8 @@ print <<EOF;
 #include <stdio.h>
 #include <stdlib.h>
 
-static int yylex (void);
-static void yyerror (const char *msg);
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
 %}
 
 %token
@@ -223,6 +226,7 @@ EOF
 
 AT_CHECK([perl -w ./gengram.pl $2 || exit 77], 0, [stdout])
 mv stdout $1
+AT_BISON_OPTION_POPDEFS
 ])
 
 
@@ -263,7 +267,8 @@ AT_CLEANUP
 # Create FILE-NAME, containing a self checking parser for a grammar
 # requiring SIZE lookahead tokens.
 m4_define([AT_DATA_LOOKAHEAD_TOKENS_GRAMMAR],
-[AT_DATA([[gengram.pl]],
+[AT_BISON_OPTION_PUSHDEFS
+AT_DATA([[gengram.pl]],
 [[#! /usr/bin/perl -w
 
 use strict;
@@ -278,8 +283,8 @@ print <<EOF;
 # include <stdlib.h>
 # include <assert.h>
 
-static int yylex (void);
-static void yyerror (const char *msg);
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
 %}
 %union
 {
@@ -363,6 +368,7 @@ EOF
 
 AT_CHECK([perl -w ./gengram.pl $2 || exit 77], 0, [stdout])
 mv stdout $1
+AT_BISON_OPTION_POPDEFS
 ])
 
 
@@ -390,7 +396,8 @@ AT_CLEANUP
 # ------------------------------------------------
 # A parser specialized in torturing the stack size.
 m4_define([AT_DATA_STACK_TORTURE],
-[# A grammar of parens growing the stack thanks to right recursion.
+[AT_BISON_OPTION_PUSHDEFS([$2])
+# A grammar of parens growing the stack thanks to right recursion.
 # exp:
 AT_DATA([input.y],
 [[%{
@@ -399,8 +406,8 @@ AT_DATA([input.y],
 #include <stdio.h>
 #include <stdlib.h>
 ]$1[
-  static int yylex (void);
-  static void yyerror (const char *msg);
+  ]AT_YYLEX_DECLARE[
+  ]AT_YYERROR_DECLARE[
 %}
 ]$2[
 %error-verbose
@@ -409,12 +416,7 @@ AT_DATA([input.y],
 %%
 exp: WAIT_FOR_EOF exp | ;
 %%
-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-}
-
+]AT_YYERROR_DEFINE[
 static int
 yylex (void)
 {
@@ -462,6 +464,7 @@ main (int argc, const char **argv)
   }
 }
 ]])
+AT_BISON_OPTION_POPDEFS([$2])
 AT_BISON_CHECK([-o input.c input.y])
 AT_COMPILE([input])
 ])