There are many macros that are defined and used just
once (b4_public_if, b4_abstract_if, etc.). That's overkill. Rather,
let's define a macro to build the "public class YYParser" line.
It appears that the same syntax with "extends", "abstract", etc. is
implemented in the D parser, which looks very fishy...
* data/skeletons/d.m4, data/skeletons/java.m4 (b4_public_if)
(b4_abstract_if, b4_final_if, b4_strictfp_if): Replace with
(b4_parser_class_declaration): this.
* data/skeletons/lalr1.d, data/skeletons/lalr1.java: Adjust.
The previous name was historical and inconsistent.
* src/muscle-tab.c (define_directive): Use the proper value passing
syntax, based on the muscle kind.
(muscle_percent_variable_update): Use the right value passing syntax.
Migrate from parser_class_name to api.parser.class.
* data/skeletons: Migrate from parser_class_name to api.parser.class.
* doc/bison.texi (%define Summary): Document both parser_class_name
and api.parser.class.
Promote the latter over the former.
