new file mode 100644
--- /dev/null
+++ b/m4/mempcpy.m4
@@ -0,0 +1,23 @@
+# mempcpy.m4 serial 1
+dnl Copyright (C) 2003 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License.  As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
+
+AC_DEFUN([gl_FUNC_MEMPCPY],
+[
+  dnl Persuade glibc <string.h> to declare mempcpy().
+  AC_REQUIRE([AC_GNU_SOURCE])
+
+  AC_REPLACE_FUNCS(mempcpy)
+  if test $ac_cv_func_mempcpy = no; then
+    gl_PREREQ_MEMPCPY
+  fi
+])
+
+# Prerequisites of lib/mempcpy.c.
+AC_DEFUN([gl_PREREQ_MEMPCPY], [
+  :
+])