(add_builtin): ok for __gss_mech_initialize() to return NULL

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@20625 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/gssapi/mech/gss_mech_switch.c

@@ -173,6 +173,10 @@ add_builtin(gssapi_mech_interface mech)
     struct _gss_mech_switch *m;
     OM_uint32 minor_status;
 
+    /* not registering any mech is ok */
+    if (mech == NULL)
+	return 0;
+
     m = malloc(sizeof(*m));
     if (m == NULL)
 	return 1;