diff --git a/refpolicy/policy/support/misc_macros.spt b/refpolicy/policy/support/misc_macros.spt
index bae5d97f0..3471b668c 100644
--- a/refpolicy/policy/support/misc_macros.spt
+++ b/refpolicy/policy/support/misc_macros.spt
@@ -11,6 +11,13 @@
 #
 define(`shiftn',`ifelse($1,0,`shift($*)',`shiftn(decr($1),shift(shift($*)))')')
 
+#
+# ifndef(expr,true_block,false_block)
+#
+# m4 does not have this.
+#
+define(`ifndef',`ifdef(`$1',`$3',`$2')')
+
 #
 # __endline__
 #