api.prefix.

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.