Since we now use obstacks, more % directives can be enabled.

* src/lex.c (percent_table): Also accept `%yacc',
`%fixed_output_files', `%defines', `%no_parser', `%verbose', and
`%debug'.
Handle the actions for `%semantic_parser' and `%pure_parser' here,
instead of returning a token.
* src/lex.h (SEMANTIC_PARSER, PURE_PARSER): Remove, unused.
* src/reader.c (read_declarations): Adjust.
* src/files.c (open_files): Don't call `compute_base_names', don't
compute `attrsfile' since they depend upon data which might be
*in* the input file now.
(output_files): Do it here.
* src/output.c (output_headers): Document the fact that this patch
introduces a guaranteed SEGV for semantic parsers.
* doc/bison.texinfo: Document them.
* tests/suite.at: Exercise these %options.

src/reader.c

@@ -931,6 +931,7 @@ read_declarations (void)
 	    case EXPECT:
 	      parse_expect_decl ();
 	      break;
+
 	    case THONG:
 	      parse_thong_decl ();
 	      break;
@@ -947,14 +948,6 @@ read_declarations (void)
 	      parse_assoc_decl (non_assoc);
 	      break;
 
-	    case SEMANTIC_PARSER:
-	      semantic_parser = 1;
-	      break;
-
-	    case PURE_PARSER:
-	      pure_parser = 1;
-	      break;
-
 	    case NOOP:
 	      break;