Merge branch 'maint'

* maint:
  c++: shorten the assertions that check whether tokens are correct
  c++: don't glue functions together
  lalr1.cc: YY_ASSERT should use api.prefix
  c++: don't use YY_ASSERT at all if parse.assert is disabled
  c++: style: follow the Bison m4 quoting pattern
  yacc.c: provide the Bison version as an integral macro
  regen
  style: make conversion of version string to int public
  %require: accept version numbers with three parts ("3.7.4")
  yacc.c: fix #definition of YYEMPTY
  gnulib: update
  doc: fix incorrect section title
  doc: minor grammar fixes in counterexamples section

data/skeletons/c.m4

@@ -58,11 +58,11 @@ m4_define([b4_cpp_guard_close],
 # b4_pull_flag if they use the values of the %define variables api.pure or
 # api.push-pull.
 m4_define([b4_identification],
-[[/* Identify Bison output.  */
-#define YYBISON 1
+[[/* Identify Bison output, and Bison version.  */
+#define YYBISON ]b4_version[
 
-/* Bison version.  */
-#define YYBISON_VERSION "]b4_version["
+/* Bison version string.  */
+#define YYBISON_VERSION "]b4_version_string["
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME ]b4_skeleton[]m4_ifdef([b4_pure_flag], [[
@@ -520,10 +520,11 @@ m4_define([b4_token_define],
 # ----------------
 # Output the definition of the tokens.
 m4_define([b4_token_defines],
-[b4_any_token_visible_if([/* Token kinds.  */
-m4_join([
+[[/* Token kinds.  */
+#define ]b4_symbol([-2], [id])[ -2
+]m4_join([
 ], b4_symbol_map([b4_token_define]))
-])])
+])
 
 
 # b4_token_enum(TOKEN-NUM)