yacc.c: provide the Bison version as an integral macro

Suggested by Balazs Scheidler.
https://github.com/akimd/bison/issues/55

* src/muscle-tab.c (muscle_init): Move/rename `b4_version` to/as...
* src/output.c (prepare): `b4_version_string`.
Also define `b4_version`.
* data/skeletons/bison.m4, data/skeletons/c.m4, data/skeletons/d.m4,
* data/skeletons/java.m4: Adjust.
* doc/bison.texi: Document it.

src/muscle-tab.c

@@ -127,9 +127,6 @@ muscle_init (void)
 
   muscle_table = hash_xinitialize (HT_INITIAL_CAPACITY, NULL, hash_muscle,
                                    hash_compare_muscles, muscle_entry_free);
-
-  /* Version and input file.  */
-  MUSCLE_INSERT_STRING ("version", VERSION);
 }
 
 

src/output.c

@@ -42,6 +42,7 @@
 #include "scan-skel.h"
 #include "symtab.h"
 #include "tables.h"
+#include "strversion.h"
 
 static struct obstack format_obstack;
 
@@ -807,6 +808,9 @@ prepare (void)
   char const *cp = getenv ("BISON_USE_PUSH_FOR_PULL");
   bool use_push_for_pull_flag = cp && *cp && strtol (cp, 0, 10);
 
+  /* Versions.  */
+  MUSCLE_INSERT_STRING ("version_string", VERSION);
+  MUSCLE_INSERT_INT ("version", strversion_to_int (VERSION));
   MUSCLE_INSERT_INT ("required_version", required_version);
 
   /* Flags. */

src/parse-gram.c

@@ -46,7 +46,7 @@
    USER NAME SPACE" below.  */
 
 /* Identify Bison output.  */
-#define YYBISON 1
+#define YYBISON 30703
 
 /* Bison version.  */
 #define YYBISON_VERSION "3.7.3.7-d831b"