diff --git a/m4/socklen.m4 b/m4/socklen.m4
new file mode 100644
index 000000000..c26a2813a
--- /dev/null
+++ b/m4/socklen.m4
@@ -0,0 +1,21 @@
+# socklen.m4 serial 1
+dnl Copyright (C) 2005 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 Simon Josefsson.
+
+AC_DEFUN([gl_SOCKLEN_T],
+[
+  AC_CHECK_HEADERS_ONCE(sys/types.h sys/socket.h)
+  AC_CHECK_TYPE([socklen_t],, [AC_DEFINE([socklen_t], [int],
+                [Map `socklen_t' to `int' if it is missing.])], [
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#endif)
+])
+])