Remove the so called hairy (semantic) parsers.

* src/system.h (EXT_GUARD_C, EXT_STYPE_H): Remove.
* src/gram.h, src/gram.c (semantic_parser): Remove.
(rule_t): Remove the guard and guard_line members.
* src/lex.h (token_t): remove tok_guard.
* src/options.c (option_table): Remove %guard and %semantic_parser
support.
* src/output.c, src/output.h (guards_output): Remove.
(prepare): Adjust.
(token_definitions_output): Don't output the `T'
tokens (???).
(output_skeleton): Don't output the guards.
* src/files.c, src/files.c (attrsfile): Remove.
* src/reader.c (symbol_list): Remove the guard and guard_line
members.
Adjust dependencies.
(parse_guard): Remove.
* data/bison.hairy: Remove.
* doc/bison.texinfo (Environment Variables): Remove occurrences of
BISON_HAIRY.

src/gram.h

@@ -47,7 +47,7 @@
    Therefore 0 cannot be used, since it would be both the rule number
    0, and the token EOF).
 
-   Actions and guards are accessed via the rule number.
+   Actions are accessed via the rule number.
 
    The rules themselves are described by several arrays: amongst which
    RITEM, and RULES.
@@ -150,9 +150,6 @@ typedef struct rule_s
 
   const char *action;
   int action_line;
-
-  const char *guard;
-  int guard_line;
 } rule_t;
 
 extern struct rule_s *rules;
@@ -166,11 +163,6 @@ extern symbol_t **symbols;
 extern token_number_t *token_translations;
 extern int max_user_token_number;
 
-/* SEMANTIC_PARSER is nonzero if the input file says to use the hairy
-   parser that provides for semantic error recovery.  If it is zero,
-   the yacc-compatible simplified parser is used.  */
-
-extern int semantic_parser;
 
 /* PURE_PARSER is nonzero if should generate a parser that is all pure
    and reentrant.  */