Merge GDB 7.5.1

gdb/gnulib/m4/stddef_h.m4

-dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 2
-dnl Copyright (C) 2009, 2010, 2011 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.
-
-AC_DEFUN([gl_STDDEF_H],
-[
-  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
-  AC_REQUIRE([gt_TYPE_WCHAR_T])
-  if test $gt_cv_c_wchar_t = no; then
-    HAVE_WCHAR_T=0
-    STDDEF_H=stddef.h
-  fi
-  AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
-    [gl_cv_decl_null_works],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
-      int test[2 * (sizeof NULL == sizeof (void *)) -1];
-]])],
-      [gl_cv_decl_null_works=yes],
-      [gl_cv_decl_null_works=no])])
-  if test $gl_cv_decl_null_works = no; then
-    REPLACE_NULL=1
-    STDDEF_H=stddef.h
-  fi
-  if test -n "$STDDEF_H"; then
-    gl_CHECK_NEXT_HEADERS([stddef.h])
-  fi
-])
-
-AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
-[
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
-  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
-])
-
-AC_DEFUN([gl_STDDEF_H_DEFAULTS],
-[
-  dnl Assume proper GNU behavior unless another module says otherwise.
-  REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
-  HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
-  STDDEF_H='';                   AC_SUBST([STDDEF_H])
-])