diff --git a/first/core.mk b/first/core.mk
index f1530d4d9..1dc82c5b9 100644
--- a/first/core.mk
+++ b/first/core.mk
@@ -13,7 +13,7 @@ define cfile-rule
 $o: $s
 	@echo CC $o
 	@mkdir -p $(dir $o)
-	@$(CC) $(CFLAGS) $(cflags) -MM -MQ $d -o $d $s
+	@$(CC) $(CFLAGS) $(cflags) -MM -MQ $o -o $d $s
 	$(hide) $(CC) $(CFLAGS) $(cflags) -c -o $o $s
 endef