Index: flag.c
===================================================================
--- flag.c	(revision 5801)
+++ flag.c	(revision 5802)
@@ -68,3 +68,20 @@
 	}
 	f->unknowns = NULL;
 }
+
+int pcb_flag_eq(pcb_flag_t *f1, pcb_flag_t *f2)
+{
+	if (f1->f != f2->f)
+		return 0;
+
+	if (f1->q != f2->q)
+		return 0;
+
+	if (f1->int_conn_grp != f2->int_conn_grp)
+		return 0;
+
+	/* WARNING: ignore unknowns for now: the only place where we use this function,
+	undo.c, won't care */
+
+	return (memcmp(f1->t, &f2->t, sizeof(f1->t)) == 0);
+}