diff --git a/acinclude.m4 b/acinclude.m4
index 1d0197c5c..7fd37ff05 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -6,4 +6,4 @@ dnl
 
 dnl $xId: misc.m4,v 1.1 1997/12/14 15:59:04 joda Exp $
 dnl
-define(upcase,`echo $1 | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ`)dnl
+m4_define([upcase],`echo $1 | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ`)dnl