api.prefix.

* data/c.m4 (b4_api_prefix, b4_api_PREFIX): New.
(b4_prefix, b4_union_name, b4_token_enums, b4_declare_yylstype): Use them.
* data/glr.c, data/yacc.c, data/glr.cc, data/lalr1.cc: Use them to change
the prefix of exported preprocessor symbols.
* src/getargs.c (usage): Ditto.
* tests/headers.at (Several parsers): New.
* tests/local.at (AT_API_PREFIX): New.
AT_YYSTYPE, AT_YYLTYPE): Adjust.
* doc/bison.texi (Multiple Parsers): Move documentation of %name-prefix to...
(Table of Symbols): here.
(Multiple Parsers): Document api.prefix.
(%define Summary): Point to it.
Use @code for variable names.
(Bison Options): -p/--name-prefix are obsoleted.
* NEWS: Announce api.prefix.

tests/local.at

@@ -145,6 +145,8 @@ m4_pushdef([AT_API_prefix],
 [m4_bmatch([$3], [%define api\.prefix ".*"],
            [m4_bregexp([$3], [%define api\.prefix "\([^""]*\)"], [\1])],
            [yy])])
+m4_pushdef([AT_API_PREFIX],
+[m4_toupper(AT_API_prefix)])
 # yyerror receives the location if %location & %pure & (%glr or %parse-param).
 m4_pushdef([AT_YYERROR_ARG_LOC_IF],
 [AT_GLR_OR_PARAM_IF([AT_PURE_AND_LOC_IF([$1], [$2])],
@@ -165,10 +167,10 @@ m4_pushdef([AT_PURE_LEX_IF],
 
 m4_pushdef([AT_YYSTYPE],
 [AT_SKEL_CC_IF([AT_NAME_PREFIX[::parser::semantic_type]],
-               [[YYSTYPE]])])
+               [AT_API_PREFIX[STYPE]])])
 m4_pushdef([AT_YYLTYPE],
 [AT_SKEL_CC_IF([AT_NAME_PREFIX[::parser::location_type]],
-               [[YYLTYPE]])])
+               [AT_API_PREFIX[LTYPE]])])
 
 
 AT_PURE_LEX_IF(
@@ -221,6 +223,7 @@ 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_API_prefix])
 m4_popdef([AT_NAME_PREFIX])
 m4_popdef([AT_GLR_OR_PARAM_IF])