Index: trunk/src/flag.c
===================================================================
--- trunk/src/flag.c	(revision 5801)
+++ trunk/src/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);
+}
Index: trunk/src/flag.h
===================================================================
--- trunk/src/flag.h	(revision 5801)
+++ trunk/src/flag.h	(revision 5802)
@@ -216,7 +216,8 @@
 	} \
 } while(0)
 
-#define PCB_FLAG_EQ(F1,F2)	(memcmp (&F1, &F2, sizeof(pcb_flag_t)) == 0)
+int pcb_flag_eq(pcb_flag_t *f1, pcb_flag_t *f2);
+#define PCB_FLAG_EQ(F1,F2)	pcb_flag_eq(&(F1), &(F2))
 
 #define PCB_FLAG_THERM(L)		(0xf << (4 *((L) % 2)))