Use gnulib-tool to create gnulib source files.

* Add gnulib files generated by gnulib-tool in build-aux, m4 and
    grub-core/gnulib directories
    * .bzignore: Add **/.deps and autogenerated gnulib files
    * configure.ac: Assign auxiliary directory to build-aux, add invocation
    of gnulib macros, add grub-core/gnulib/Makefile
    * Makefile.am: Add gnulib directory in SUBDIRS (removing unnecessary .),
    include m4 directory to aclocal.
    * Makefile.util.def: Remove direct compilation of gnulib source files
    and use the new grub-core/gnulib/libgnu.a.
    * build-aux/config.rpath: move config.rpath from top directory to
    build-aux
    * conf/Makefile.common: Remove the macro _GL_UNUSED already defined
    in gnulib headers
    * conf/Makefile.extra-dist: Add m4/gnulib-cache.m4
    * grub-core/Makefile.core.def: Remove unnecessary extra_dist
    * grub-core/lib/posix_wrap/localcharset.h (locale_charset): Update
    header.
    * grub-core/lib/posix_wrap/langinfo.h (nl_langinfo): Return static
    string.

m4/longlong.m4

@@ -0,0 +1,106 @@
+# longlong.m4 serial 14
+dnl Copyright (C) 1999-2007, 2009-2010 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+# Define HAVE_LONG_LONG_INT if 'long long int' works.
+# This fixes a bug in Autoconf 2.61, but can be removed once we
+# assume 2.62 everywhere.
+
+# Note: If the type 'long long int' exists but is only 32 bits large
+# (as on some very old compilers), HAVE_LONG_LONG_INT will not be
+# defined. In this case you can treat 'long long int' like 'long int'.
+
+AC_DEFUN([AC_TYPE_LONG_LONG_INT],
+[
+  AC_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
+    [AC_LINK_IFELSE(
+       [_AC_TYPE_LONG_LONG_SNIPPET],
+       [dnl This catches a bug in Tandem NonStop Kernel (OSS) cc -O circa 2004.
+        dnl If cross compiling, assume the bug isn't important, since
+        dnl nobody cross compiles for this platform as far as we know.
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[@%:@include <limits.h>
+               @%:@ifndef LLONG_MAX
+               @%:@ define HALF \
+                        (1LL << (sizeof (long long int) * CHAR_BIT - 2))
+               @%:@ define LLONG_MAX (HALF - 1 + HALF)
+               @%:@endif]],
+             [[long long int n = 1;
+               int i;
+               for (i = 0; ; i++)
+                 {
+                   long long int m = n << i;
+                   if (m >> i != n)
+                     return 1;
+                   if (LLONG_MAX / 2 < m)
+                     break;
+                 }
+               return 0;]])],
+          [ac_cv_type_long_long_int=yes],
+          [ac_cv_type_long_long_int=no],
+          [ac_cv_type_long_long_int=yes])],
+       [ac_cv_type_long_long_int=no])])
+  if test $ac_cv_type_long_long_int = yes; then
+    AC_DEFINE([HAVE_LONG_LONG_INT], [1],
+      [Define to 1 if the system has the type `long long int'.])
+  fi
+])
+
+# Define HAVE_UNSIGNED_LONG_LONG_INT if 'unsigned long long int' works.
+# This fixes a bug in Autoconf 2.61, but can be removed once we
+# assume 2.62 everywhere.
+
+# Note: If the type 'unsigned long long int' exists but is only 32 bits
+# large (as on some very old compilers), AC_TYPE_UNSIGNED_LONG_LONG_INT
+# will not be defined. In this case you can treat 'unsigned long long int'
+# like 'unsigned long int'.
+
+AC_DEFUN([AC_TYPE_UNSIGNED_LONG_LONG_INT],
+[
+  AC_CACHE_CHECK([for unsigned long long int],
+    [ac_cv_type_unsigned_long_long_int],
+    [AC_LINK_IFELSE(
+       [_AC_TYPE_LONG_LONG_SNIPPET],
+       [ac_cv_type_unsigned_long_long_int=yes],
+       [ac_cv_type_unsigned_long_long_int=no])])
+  if test $ac_cv_type_unsigned_long_long_int = yes; then
+    AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
+      [Define to 1 if the system has the type `unsigned long long int'.])
+  fi
+])
+
+# Expands to a C program that can be used to test for simultaneous support
+# of 'long long' and 'unsigned long long'. We don't want to say that
+# 'long long' is available if 'unsigned long long' is not, or vice versa,
+# because too many programs rely on the symmetry between signed and unsigned
+# integer types (excluding 'bool').
+AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
+[
+  AC_LANG_PROGRAM(
+    [[/* For now, do not test the preprocessor; as of 2007 there are too many
+         implementations with broken preprocessors.  Perhaps this can
+         be revisited in 2012.  In the meantime, code should not expect
+         #if to work with literals wider than 32 bits.  */
+      /* Test literals.  */
+      long long int ll = 9223372036854775807ll;
+      long long int nll = -9223372036854775807LL;
+      unsigned long long int ull = 18446744073709551615ULL;
+      /* Test constant expressions.   */
+      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
+                     ? 1 : -1)];
+      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
+                     ? 1 : -1)];
+      int i = 63;]],
+    [[/* Test availability of runtime routines for shift and division.  */
+      long long int llmax = 9223372036854775807ll;
+      unsigned long long int ullmax = 18446744073709551615ull;
+      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
+              | (llmax / ll) | (llmax % ll)
+              | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
+              | (ullmax / ull) | (ullmax % ull));]])
+])