diff --git a/ChangeLog b/ChangeLog
index 38ed367bc0..be2d6bed62 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Dec 11 16:19:26 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* Makefile.in, */Makefile.sub (CP, MV): added.
+
+	* common.mk (.y.c): not discard the old target until successfully
+	  created.
+
 Tue Dec 11 15:20:39 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* object.c (Init_Object): singleton_method_{added,removed,undefined}
diff --git a/Makefile.in b/Makefile.in
index 82e5a235bd..702fa518d6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -81,6 +81,8 @@ ARCHFILE      = @ARCHFILE@
 SETUP         =
 EXTSTATIC     = @EXTSTATIC@
 
+CP            = cp
+MV            = mv
 RM            = rm -f
 NM            = @NM@
 AR            = @AR@
diff --git a/bcc32/Makefile.sub b/bcc32/Makefile.sub
index c79e586402..971b62c297 100644
--- a/bcc32/Makefile.sub
+++ b/bcc32/Makefile.sub
@@ -67,6 +67,8 @@ BASERUBY = ruby
 PURIFY =
 AUTOCONF = autoconf
 RM = $(srcdir:/=\)\win32\rm.bat
+CP = copy > nul
+MV = ren > nul
 
 !if !defined(PROCESSOR_ARCHITECTURE)
 PROCESSOR_ARCHITECTURE = x86
diff --git a/common.mk b/common.mk
index 543088bb82..4fce91be38 100644
--- a/common.mk
+++ b/common.mk
@@ -355,8 +355,9 @@ PHONY:
 
 {$(srcdir)}.y.c:
 	$(YACC) $(YFLAGS) -o y.tab.c $<
-	sed -f $(srcdir)/tool/ytab.sed -e "/^#/s!y\.tab\.c!$@!" y.tab.c > $@
-	@$(RM) y.tab.c
+	sed -f $(srcdir)/tool/ytab.sed -e "/^#/s!y\.tab\.c!$@!" y.tab.c > $@.new
+	@$(RM) $@ y.tab.c
+	@$(MV) $@.new $@
 
 acosh.$(OBJEXT): {$(VPATH)}acosh.c
 alloca.$(OBJEXT): {$(VPATH)}alloca.c
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 50dcc09aea..276dc4e84c 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -50,6 +50,8 @@ AR = lib -nologo
 PURIFY =
 AUTOCONF = autoconf
 RM = $(COMSPEC) /C $(srcdir:/=\)\win32\rm.bat
+CP = copy > nul
+MV = ren > nul
 !if !defined(BASERUBY)
 BASERUBY = ruby
 !endif
diff --git a/wince/Makefile.sub b/wince/Makefile.sub
index 07fc4d41a5..a7de413f40 100644
--- a/wince/Makefile.sub
+++ b/wince/Makefile.sub
@@ -44,6 +44,8 @@ AR = lib -nologo
 PURIFY =
 AUTOCONF = autoconf
 RM = $(srcdir)\win32\rm.bat
+CP = copy > nul
+MV = ren > nul
 !if !defined(BASERUBY)
 BASERUBY = ruby
 !endif