-# memmem.m4 serial 3
+# memmem.m4 serial 4
dnl Copyright (C) 2002, 2003, 2004, 2007 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 Persuade glibc <string.h> to declare memmem().
AC_REQUIRE([AC_GNU_SOURCE])
+ AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_REPLACE_FUNCS(memmem)
AC_CHECK_DECLS_ONCE(memmem)
if test $ac_cv_have_decl_memmem = no; then