maint: update to latest gnulib

'make syntax-check' wants a newer gnulib for 2014 copyright.

Also, a couple of fixes for bootstrap issues reported on IRC:
- on some older glibc systems, ./configure could deadlock due to
a glibc malloc bug
- on FreeBSD systems, a broken autom4te coupled with gettext
0.18.3 prevents bootstrap; we can't work around it, but can at
least inform the user why they have a problem

And as always, portability fixes in other modules, some of which
are used by libvirt.

* .gnulib: Update to latest, in part for bootstrap improvements,
and for the new year.
* bootstrap: Resync to gnulib.
* gnulib/local/m4/ssize_t.m4.diff: Regenerate.

Signed-off-by: Eric Blake <eblake@redhat.com>

.gnulib

@@ -1 +1 @@
-Subproject commit 831b84c59ef413c57a36b67344467d66a8a2ba70
+Subproject commit c7802e2b418c40fa2bd270cf241314d0c8433a26

bootstrap

@@ -1,10 +1,10 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2013-08-15.22; # UTC
+scriptversion=2013-12-05.23; # UTC
 
 # Bootstrap this package from checked-out sources.
 
-# Copyright (C) 2003-2013 Free Software Foundation, Inc.
+# Copyright (C) 2003-2014 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -551,6 +551,14 @@ if ! printf "$buildreq" | check_versions; then
   fi
 fi
 
+# Warn the user if autom4te appears to be broken; this causes known
+# issues with at least gettext 0.18.3.
+probe=$(echo 'm4_quote([hi])' | autom4te -l M4sugar -t 'm4_quote:$%' -)
+if test "x$probe" != xhi; then
+  warn_ "WARNING: your autom4te wrapper eats stdin;"
+  warn_ "if bootstrap fails, consider upgrading your autotools"
+fi
+
 echo "$0: Bootstrapping from checked-out $package sources..."
 
 # See if we can use gnulib's git-merge-changelog merge driver.

gnulib/local/m4/ssize_t.m4.diff

@@ -5,7 +5,7 @@ index 209d64c..5ea72a1 100644
 @@ -1,4 +1,4 @@
 -# ssize_t.m4 serial 5 (gettext-0.18.2)
 +# ssize_t.m4 serial 6 (gettext-0.18.2)
- dnl Copyright (C) 2001-2003, 2006, 2010-2013 Free Software Foundation, Inc.
+ dnl Copyright (C) 2001-2003, 2006, 2010-2014 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
 @@ -17,7 +17,21 @@ AC_DEFUN([gt_TYPE_SSIZE_T],