diff --git a/common.mk b/common.mk
index d08a856d60..bf24441f3a 100644
--- a/common.mk
+++ b/common.mk
@@ -464,8 +464,6 @@ dl_os2.$(OBJEXT): {$(VPATH)}dl_os2.c
 ia64.$(OBJEXT): {$(VPATH)}ia64.s
 	$(CC) $(CFLAGS) -c $<
 
-# when I use -I., there is confliction at "OpenFile"
-# so, set . into environment varible "include"
 win32.$(OBJEXT): {$(VPATH)}win32.c $(RUBY_H_INCLUDES)
 
 ###