Merge tag 'v2.5.1_rc2'

Bison 2.5.1_rc2.

* tag 'v2.5.1_rc2': (34 commits)
  Bison 2.5.1_rc2.
  doc: fixes.
  build: fix ChangeLog generation.
  c++: compute the header guards.
  skeletons: remove support for unused directive.
  lalr1.cc: improve Doxygen documentation.
  lalr1.cc: extract stack.hh.
  news: convert to double quotes.
  space changes.
  build: do not prototype flex-generated functions.
  build: fix ChangeLog generation.
  Bison 2.5.1_rc1.
  tests: save/restore Autotest special files when checking XML support.
  tests: AT_SAVE_SPECIAL_FILES / AT_RESTORE_SPECIAL_FILES.
  tests: honor TESTSUITEFLAGS in all the check targets.
  build: do not enable c++ warnings on 0 when nullptr is not supported.
  maint: update gnulib.
  build: config.in.h.
  build: move silent rules.
  glr.c: reduce variable scopes.
  maint: maintainer-release-check.
  maint: shush a syntax-check.
  maint: prefer "commit message" to "log entry".
  command line: fix minor leaks.
  maint: we no longer maintain the ChangeLog.
  maint: fix the generation of the synclines for bison's parser.
  maint: regen.
  maint: import the xmemdup0 gnulib module.
  maint: remove left-over gnulib modules.
  maint: ignore files imported by autopoint.
  build: AC_PROG_LEX: use more readable variable names.
  maint: regen src/parse-gram.[ch]
  maint: simplify parse-gram.y
  maint: s/strncpy/memcpy/, when equivalent

Conflicts:
	Makefile.am
	NEWS
	data/glr.c
	data/lalr1.cc
	data/stack.hh
	examples/rpcalc/local.mk
	src/flex-scanner.h
	src/getargs.c
	src/output.c
	src/parse-gram.c
	src/parse-gram.h
	src/parse-gram.y
	tests/Makefile.am
	tests/bison.in

m4/.gitignore

@@ -38,6 +38,7 @@
 /getdtablesize.m4
 /getopt.m4
 /gettext.m4
+/glibc2.m4
 /glibc21.m4
 /gnulib-cache.m4
 /gnulib-common.m4
@@ -47,7 +48,12 @@
 /iconv.m4
 /include_next.m4
 /inline.m4
+/intdiv0.m4
+/intl.m4
+/intl.m4~
+/intldir.m4
 /intlmacosx.m4
+/intmax.m4
 /intmax_t.m4
 /inttypes-pri.m4
 /inttypes.m4
@@ -61,6 +67,7 @@
 /javacomp.m4
 /javaexec.m4
 /largefile.m4
+/lcmessage.m4
 /ldexp.m4
 /ldexpl.m4
 /lib-ld.m4
@@ -71,6 +78,7 @@
 /locale-fr.m4
 /locale-ja.m4
 /locale-zh.m4
+/lock.m4
 /longlong.m4
 /malloc.m4
 /math_h.m4
@@ -88,12 +96,13 @@
 /multiarch.m4
 /nls.m4
 /nocrash.m4
+/off_t.m4
 /open.m4
 /pathmax.m4
 /perror.m4
-/pipe.m4
 /pipe2.m4
 /po.m4
+/po.m4~
 /posix_spawn.m4
 /printf-frexp.m4
 /printf-frexpl.m4
@@ -144,14 +153,18 @@
 /sys_ioctl_h.m4
 /sys_socket_h.m4
 /sys_stat_h.m4
+/sys_types_h.m4
 /sys_wait_h.m4
+/sysexits.m4
 /threadlib.m4
 /time_h.m4
+/uintmax_t.m4
 /unistd-safer.m4
 /unistd_h.m4
 /unlocked-io.m4
 /vasnprintf.m4
 /vfprintf-posix.m4
+/visibility.m4
 /vsnprintf-posix.m4
 /vsnprintf.m4
 /vsprintf-posix.m4
@@ -167,4 +180,3 @@
 /xalloc.m4
 /xsize.m4
 /xstrndup.m4
-/sysexits.m4

m4/flex.m4

@@ -1,4 +1,4 @@
-# flex.m4 serial 1
+# flex.m4 serial 2
 # Copyright (C) 2012 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -24,7 +24,7 @@ fi])
 # and whether Lex declares yytext as a char * by default.
 m4_define([_AC_PROG_LEX_YYTEXT_DECL],
 [AC_CACHE_CHECK([whether lex is flex],
-                [ac_cv_prog_flex],
+                [ac_cv_prog_lex_is_flex],
 [cat >conftest.l <<_ACEOF[
 %option debug nodefault noinput nounput noyywrap never-interactive
 %x SC_CONF_TEST
@@ -32,15 +32,13 @@ m4_define([_AC_PROG_LEX_YYTEXT_DECL],
 a { BEGIN SC_CONF_TEST; }
 ]_ACEOF
 if _AC_DO_VAR([LEX conftest.l]); then
-  ac_cv_prog_flex=yes
+  ac_cv_prog_lex_is_flex=yes
 else
-  ac_cv_prog_flex=no
+  ac_cv_prog_lex_is_flex=no
 fi
 ])
-FLEX=
-if test $ac_cv_prog_flex = yes; then
-  AC_SUBST([FLEX], [yes])dnl
-fi
+AC_SUBST([LEX_IS_FLEX],
+         [`test "$ac_cv_prog_lex_is_flex" = yes && echo true || echo false`])dnl
 
 cat >conftest.l <<_ACEOF[
 %%