diff --git a/ChangeLog b/ChangeLog
index 577030e931..38893c7f44 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Thu Nov 22 18:11:27 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* common.mk, Makefile.in, win32/Makefile.sub (.dmyh.h): nmake merges
+	  explicit rules for same target, but not merges exlicit rules and
+	  implicit rules -- always explict rules win.  So, need to add an
+	  explist rule for probes.h.  [Bug #7421] [ruby-core:49839]
+
 Thu Nov 22 18:01:28 2012  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* Makefile.in (probes.o): add -C to ignore #include in probes.d.
diff --git a/Makefile.in b/Makefile.in
index 42cc95132e..6984bba300 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -338,6 +338,10 @@ enc/unicode/name2ctype.h: enc/unicode/name2ctype.kwd
 	$(Q) sed -e 's/RUBY_/RUBY_DTRACE_/g' -e 's/PROBES_H_TMP/PROBES_H/g' -e 's/(char \*/(const char */g' -e 's/, char \*/, const char */g' $@.tmp > $@
 	$(Q) $(RM) $@.tmp
 
+{$(VPATH)}.dmyh.h:
+	@$(ECHO) copying dummy $(DEST_FILE)
+	$(Q) $(CP) $(OS_SRC_FILE) $(OS_DEST_FILE)
+
 probes.@OBJEXT@: $(srcdir)/probes.d
 	@$(ECHO) processing probes in object files
 	$(Q) stamp="$*.stamp"; \
diff --git a/common.mk b/common.mk
index 1e4f2156b6..ba02083a42 100644
--- a/common.mk
+++ b/common.mk
@@ -901,10 +901,6 @@ $(srcdir)/probes.dmyh: {$(srcdir)}probes.d $(srcdir)/tool/gen_dummy_probes.rb
 
 probes.h: $(srcdir)/probes.$(DTRACE_EXT)
 
-{$(VPATH)}.dmyh.h:
-	@$(ECHO) copying dummy $(DEST_FILE)
-	$(Q) $(CP) $(OS_SRC_FILE) $(OS_DEST_FILE)
-
 prereq: incs srcs preludes PHONY
 
 preludes: {$(VPATH)}miniprelude.c
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index b5b75f2f7f..49159938d2 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -1067,6 +1067,10 @@ ext/extinit.obj: ext/extinit.c $(SETUP)
 	$(ECHO) compiling ext/extinit.c
 	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c ext/extinit.c
 
+probes.h: {$(srcdir)}probes.dmyh
+	@$(ECHO) copying dummy $(DEST_FILE)
+	$(Q) $(CP) $(srcdir:/=\)\probes.dmyh $(OS_DEST_FILE)
+
 INSNS	= opt_sc.inc optinsn.inc optunifs.inc insns.inc insns_info.inc \
 	  vmtc.inc vm.inc