deprecate %defines in favor of %header

This is consistent with --defines being deprecated in favor of
--header.  The directive %defines is also too similar to %define.
And %header matches nicely with api.header.name.

* src/scan-gram.l (%defines): Deprecate to %header.
(%header): Scan it.
* src/parse-gram.y (PERCENT_DEFINES): Replace with...
(PERCENT_HEADER): this.
* data/skeletons/lalr1.java
* doc/bison.texi
* tests/actions.at, tests/c++.at, tests/calc.at, tests/conflicts.at,
* tests/input.at, tests/java.at, tests/local.at, tests/output.at,
* tests/synclines.at, tests/types.at:
Convert most tests to check %header instead of %defines.

src/parse-gram.y

@@ -96,8 +96,8 @@
      string from the scanner (should be CODE). */
   static char const *translate_code_braceless (char *code, location loc);
 
-  /* Handle a %defines directive.  */
-  static void handle_defines (char const *value);
+  /* Handle a %header directive.  */
+  static void handle_header (char const *value);
 
   /* Handle a %error-verbose directive.  */
   static void handle_error_verbose (location const *loc, char const *directive);
@@ -153,7 +153,7 @@
 %define parse.error custom
 %define parse.lac full
 %define parse.trace
-%defines
+%header
 %expect 0
 %verbose
 
@@ -188,20 +188,19 @@
   PERCENT_CODE            "%code"
   PERCENT_DEFAULT_PREC    "%default-prec"
   PERCENT_DEFINE          "%define"
-  PERCENT_DEFINES         "%defines"
   PERCENT_ERROR_VERBOSE   "%error-verbose"
   PERCENT_EXPECT          "%expect"
   PERCENT_EXPECT_RR       "%expect-rr"
-  PERCENT_FLAG            "%<flag>"
   PERCENT_FILE_PREFIX     "%file-prefix"
+  PERCENT_FLAG            "%<flag>"
   PERCENT_GLR_PARSER      "%glr-parser"
+  PERCENT_HEADER          "%header"
   PERCENT_INITIAL_ACTION  "%initial-action"
   PERCENT_LANGUAGE        "%language"
   PERCENT_NAME_PREFIX     "%name-prefix"
   PERCENT_NO_DEFAULT_PREC "%no-default-prec"
   PERCENT_NO_LINES        "%no-lines"
-  PERCENT_NONDETERMINISTIC_PARSER
-                          "%nondeterministic-parser"
+  PERCENT_NONDETERMINISTIC_PARSER "%nondeterministic-parser"
   PERCENT_OUTPUT          "%output"
   PERCENT_PURE_PARSER     "%pure-parser"
   PERCENT_REQUIRE         "%require"
@@ -339,8 +338,7 @@ prologue_declaration:
       muscle_percent_define_insert ($2, @$, $3.kind, $3.chars,
                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
     }
-| "%defines"                       { header_flag = true; }
-| "%defines" STRING                { handle_defines ($2); }
+| "%header" string.opt             { handle_header ($2); }
 | "%error-verbose"                 { handle_error_verbose (&@$, $1); }
 | "%expect" INT_LITERAL            { expected_sr_conflicts = $2; }
 | "%expect-rr" INT_LITERAL         { expected_rr_conflicts = $2; }
@@ -485,6 +483,12 @@ precedence_declarator:
 | "%precedence" { $$ = precedence_assoc; }
 ;
 
+%type <char*> string.opt;
+string.opt:
+  %empty  { $$ = NULL; }
+| STRING  { $$ = $1; }
+;
+
 tag.opt:
   %empty { $$ = NULL; }
 | TAG    { $$ = $1; }
@@ -947,13 +951,16 @@ add_param (param_type type, char *decl, location loc)
 
 
 static void
-handle_defines (char const *value)
+handle_header (char const *value)
 {
   header_flag = true;
-  char *file = unquote (value);
-  spec_header_file = xstrdup (file);
-  gram_scanner_last_string_free ();
-  unquote_free (file);
+  if (value)
+    {
+      char *file = unquote (value);
+      spec_header_file = xstrdup (file);
+      gram_scanner_last_string_free ();
+      unquote_free (file);
+    }
 }
 
 

src/scan-gram.l

@@ -245,15 +245,16 @@ eqopt    ({sp}=)?
   "%debug"                          RETURN_PERCENT_FLAG ("parse.trace");
   "%default-prec"                   return BISON_DIRECTIVE (DEFAULT_PREC);
   "%define"                         return BISON_DIRECTIVE (DEFINE);
-  "%defines"                        return BISON_DIRECTIVE (DEFINES);
+  "%defines"                        return BISON_DIRECTIVE (HEADER); // Deprecated in 3.8.
   "%destructor"                     return BISON_DIRECTIVE (DESTRUCTOR);
   "%dprec"                          return BISON_DIRECTIVE (DPREC);
   "%empty"                          return BISON_DIRECTIVE (EMPTY);
   "%expect"                         return BISON_DIRECTIVE (EXPECT);
   "%expect-rr"                      return BISON_DIRECTIVE (EXPECT_RR);
   "%file-prefix"                    RETURN_VALUE (PERCENT_FILE_PREFIX, uniqstr_new (yytext));
-  "%initial-action"                 return BISON_DIRECTIVE (INITIAL_ACTION);
   "%glr-parser"                     return BISON_DIRECTIVE (GLR_PARSER);
+  "%header"                         return BISON_DIRECTIVE (HEADER);
+  "%initial-action"                 return BISON_DIRECTIVE (INITIAL_ACTION);
   "%language"                       return BISON_DIRECTIVE (LANGUAGE);
   "%left"                           return PERCENT_LEFT;
   "%lex-param"                      RETURN_PERCENT_PARAM (lex);