portability: use -DGNULIB_POSIXCHECK.

Reported by Eric Blake.  See discussions at
<http://lists.gnu.org/archive/html/bug-bison/2009-09/msg00008.html>
and
<http://lists.gnu.org/archive/html/bug-gnulib/2009-10/msg00108.html>.
* HACKING (Release checks): Suggest -DGNULIB_POSIXCHECK.
* bootstrap.conf (gnulib_modules): Add all the printf modules
suggested by -DGNULIB_POSIXCHECK.  Add realloc-posix as
suggested by -DGNULIB_POSIXCHECK for gnulib's own vasnprintf.c.
(excluded_files): Remove m4/printf-posix.m4.
* tests/atlocal.in (LIBS): As for LDADD in src/Makefile.am, add
lib/libbison.a so gnulib libraries can be linked.
(cherry picked from commit 5c99151aeb)

Conflicts:

	lib/.cvsignore
	lib/.gitignore
	m4/.cvsignore
	m4/.gitignore

bootstrap.conf

@@ -20,9 +20,13 @@ gnulib_modules='
   announce-gen argmatch assert config-h c-strcase configmake dirname
   error extensions fopen-safer gendocs getopt-gnu gettext
   git-version-gen hash inttypes javacomp-script javaexec-script
-  maintainer-makefile malloc mbswidth obstack quote quotearg stdbool
-  stpcpy strerror strtoul strverscmp unistd unistd-safer unlocked-io
-  update-copyright unsetenv verify warnings xalloc xalloc-die xstrndup
+  maintainer-makefile malloc mbswidth obstack quote quotearg
+  realloc-posix stdbool stpcpy strerror strtoul strverscmp unistd
+  unistd-safer unlocked-io update-copyright unsetenv verify warnings
+  xalloc xalloc-die xstrndup
+
+  fprintf-posix printf-posix snprintf-posix sprintf-posix
+  vsnprintf-posix vsprintf-posix
 '
 
 # Additional xgettext options to use.  Use "\\\newline" to break lines.
@@ -52,7 +56,6 @@ excluded_files='
     m4/lcmessage.m4
     m4/lock.m4
     m4/longdouble.m4
-    m4/printf-posix.m4
     m4/signed.m4
     m4/size_max.m4
     m4/uintmax_t.m4