glr.cc: don't leak glr.c/glr.cc scaffolding to the user

Until we have a decent reimplementation of glr.cc, we have to use
tricks to shoehorn C++ symbols to the C engine of glr.c.  Some of them
are done via #define.  Unfortunately in Bison 3.6 some of these we
done in the header file, which broke valid user code.

Reported by Egor Pugin.
https://lists.gnu.org/r/bug-bison/2020-06/msg00003.html

* data/skeletons/glr.cc: Stop playing tricks with b4_pre_epilogue.
(b4_glr_cc_setup, b4_glr_cc_cleanup): New.
Much cleaner way to instal glr.cc's scaffolding around glr.c.
* data/skeletons/glr.c: Adjust to use them.

NEWS

@@ -2,6 +2,10 @@ GNU Bison NEWS
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
+** Bug fixes
+
+  In glr.cc some internal macros leaked in the user's code, and could damage
+  access to the token kinds.
 
 * Noteworthy changes in release 3.6.3 (2020-06-03) [stable]
 

TODO

@@ -1,4 +1,7 @@
 * Bison 3.7
+** glr.cc
+Get rid of global_tokens_and_yystype.
+
 ** Bistromathic
 - Hitting tab on a line with a syntax error is ugly
 
@@ -148,6 +151,9 @@ Les catégories d'avertissements incluent :
 Line -1 and -3 should mention CATEGORIE, not CATEGORY.
 
 * Bison 3.8
+** Rewrite glr.cc
+Get rid of scaffolding in glr.c.
+
 ** Unit rules / Injection rules (Akim Demaille)
 Maybe we could expand unit rules (or "injections", see
 https://homepages.cwi.nl/~daybuild/daily-books/syntax/2-sdf/sdf.html), i.e.,

data/skeletons/glr.c

@@ -230,7 +230,9 @@ b4_copyright([Skeleton implementation for Bison GLR parsers in C],
 
 ]b4_defines_if([[#include "@basename(]b4_spec_header_file[@)"]],
                [b4_shared_declarations])[
-]b4_declare_symbol_enum[
+
+]b4_glr_cc_if([b4_glr_cc_setup],
+              [b4_declare_symbol_enum])[
 
 /* Default (constant) value used for initialization for null
    right-hand sides.  Unlike the standard yacc.c template, here we set
@@ -2731,7 +2733,7 @@ m4_if(b4_prefix, [yy], [],
 #define yynerrs ]b4_prefix[nerrs]b4_locations_if([[
 #define yylloc  ]b4_prefix[lloc]])])[
 
-]m4_ifdef([b4_pre_epilogue], [b4_pre_epilogue])[]dnl This is a hack for glr.cc.  To remove when we have a better glr.cc.
+]b4_glr_cc_if([b4_glr_cc_cleanup])[
-b4_percent_code_get([[epilogue]])[]dnl
+]b4_percent_code_get([[epilogue]])[]dnl
 b4_epilogue[]dnl
 b4_output_end

data/skeletons/glr.cc

@@ -105,12 +105,6 @@ yyerror (]b4_locations_if([[const ]b4_namespace_ref::b4_parser_class[::location_
          ]])[]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param),
          ])[const char* msg);]])[
 
-]b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
-[m4_define([b4_pre_epilogue],
-[[/* The user is using the C++ token kind, not the C one. */
-#undef ]b4_symbol(0, [id])
-])])[
-
 # Hijack the epilogue to define implementations (yyerror, parser member
 # functions etc.).
 ]m4_append([b4_epilogue],
@@ -222,6 +216,53 @@ b4_namespace_close[]dnl
 ])
 
 
+# b4_glr_cc_setup
+# ---------------
+# Setup redirections for glr.c: Map the names used in c.m4 to the ones used
+# in c++.m4.
+m4_define([b4_glr_cc_setup],
+[[#undef ]b4_symbol(-2, [id])[
+#define ]b4_symbol(-2, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
+#undef ]b4_symbol(0, [id])[
+#define ]b4_symbol(0, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+#define ]b4_symbol(1, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[
+
+#ifndef ]b4_api_PREFIX[STYPE
+# define ]b4_api_PREFIX[STYPE ]b4_namespace_ref[::]b4_parser_class[::semantic_type
+#endif
+#ifndef ]b4_api_PREFIX[LTYPE
+# define ]b4_api_PREFIX[LTYPE ]b4_namespace_ref[::]b4_parser_class[::location_type
+#endif
+
+typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type yysymbol_kind_t;
+#define ]b4_symbol_prefix[YYEMPTY  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
+#define ]b4_symbol_prefix[YYerror  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYerror
+#define ]b4_symbol_prefix[YYEOF    ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
+#define ]b4_symbol_prefix[YYUNDEF  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
+]])
+
+
+# b4_glr_cc_cleanup
+# -----------------
+# Remove redirections for glr.c.
+m4_define([b4_glr_cc_cleanup],
+[b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
+[[#undef ]b4_symbol(-2, [id])[
+#undef ]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+]])[
+
+#undef ]b4_api_PREFIX[STYPE
+#undef ]b4_api_PREFIX[LTYPE
+
+#undef ]b4_symbol_prefix[YYEMPTY
+#undef ]b4_symbol_prefix[YYerror
+#undef ]b4_symbol_prefix[YYEOF
+#undef ]b4_symbol_prefix[YYUNDEF
+]])
+
+
 # b4_shared_declarations(hh|cc)
 # -----------------------------
 # Declaration that might either go into the header (if --defines, $1 = hh)
@@ -339,33 +380,11 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 ])[
 ]b4_namespace_close[
 
-]dnl Map the name used in c.m4 to the one used in c++.m4.
-[#undef ]b4_symbol(-2, [id])[
-#define ]b4_symbol(-2, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
-#undef ]b4_symbol(0, [id])[
-#define ]b4_symbol(0, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
-#undef ]b4_symbol(1, [id])[
-#define ]b4_symbol(1, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[
-
-#ifndef ]b4_api_PREFIX[STYPE
-# define ]b4_api_PREFIX[STYPE ]b4_namespace_ref[::]b4_parser_class[::semantic_type
-#endif
-#ifndef ]b4_api_PREFIX[LTYPE
-# define ]b4_api_PREFIX[LTYPE ]b4_namespace_ref[::]b4_parser_class[::location_type
-#endif
-
-]m4_define([b4_declare_symbol_enum],
-[[typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type yysymbol_kind_t;
-#define ]b4_symbol_prefix[YYEMPTY  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
-#define ]b4_symbol_prefix[YYerror  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYerror
-#define ]b4_symbol_prefix[YYEOF    ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
-#define ]b4_symbol_prefix[YYUNDEF  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
-]])[
 ]b4_percent_code_get([[provides]])[
 ]m4_popdef([b4_parse_param])dnl
-])
+])[
 
-b4_defines_if(
+]b4_defines_if(
 [b4_output_begin([b4_spec_header_file])
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
              [2002-2015, 2018-2020])[

m4/.gitignore

@@ -56,7 +56,6 @@
 /gnulib-comp.m4
 /gnulib-tool.m4
 /host-cpu-c-abi.m4
-/iconv.m4
 /include_next.m4
 /intdiv0.m4
 /intl.m4