diff --git a/macros/ChangeLog b/macros/ChangeLog
index 72c1287c92..b66b43af25 100644
--- a/macros/ChangeLog
+++ b/macros/ChangeLog
@@ -1,3 +1,7 @@
+2003-06-28  Sebastian Rittau  <srittau@jroger.in-berlin.de>
+
+	* gnome-x-checks.m4: Add third argument to AC_DEFINE.
+
 2003-05-03  Malcolm Tredinnick <malcolm@commsecure.com.au>
 	
 	* autogen.sh: Allow users to specify the binary to run instead of
diff --git a/macros/gnome-x-checks.m4 b/macros/gnome-x-checks.m4
index 1e397ef8e3..2702a93301 100644
--- a/macros/gnome-x-checks.m4
+++ b/macros/gnome-x-checks.m4
@@ -66,7 +66,7 @@ dnl	AC_MSG_RESULT("$dev_gtk")
 	fi
 
 	if test "$GNOME_HAVE_SM" = true; then
-	   AC_DEFINE(HAVE_LIBSM)
+	   AC_DEFINE(HAVE_LIBSM,, [Define if you have libSM.])
 	fi
 
 	XPM_LIBS=""