diff --git a/ChangeLog b/ChangeLog
index 9d99844d60..c50120a313 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Tue Feb 24 19:01:05 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* common.mk (main): split from exts and makes main program after
+	  building exts with miniruby, to get rid of overwriting running
+	  program.  [ruby-core:22339]
+
+	* Makefile.in, win32/Makefile.sub (RUNCMD, MKMAIN_CMD): macros to
+	  run script file.
+
+	* ext/extmk.rb (parse_args): added --command-output option which
+	  creates script file to make main program.
+
 Tue Feb 24 07:09:50 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* regex.c (re_compile_pattern): \s should include \v too.
diff --git a/Makefile.in b/Makefile.in
index 121a7cf245..921be5db19 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,5 +1,6 @@
 SHELL = /bin/sh
 NULLCMD = :
+RUNCMD = $(SHELL)
 
 #### Start of system configuration section. ####
 
@@ -93,6 +94,8 @@ OBJEXT        = @OBJEXT@
 MANTYPE	      = @MANTYPE@
 
 INSTALLED_LIST= .installed.list
+
+MKMAIN_CMD    = mkmain.sh
 #### End of variables
 
 all:
diff --git a/common.mk b/common.mk
index 0e4d658055..d153074e91 100644
--- a/common.mk
+++ b/common.mk
@@ -80,8 +80,16 @@ TESTWORKDIR   = testwork
 
 VCS           = svn
 
-all: $(MKFILES) $(PREP) $(RBCONFIG) $(LIBRUBY)
-	@$(MINIRUBY) $(srcdir)/ext/extmk.rb --make="$(MAKE)" $(EXTMK_ARGS)
+all: main
+
+main: exts
+	@$(RUNCMD) $(MKMAIN_CMD) MAKE=$(MAKE)
+
+exts: $(MKMAIN_CMD)
+
+$(MKMAIN_CMD): $(MKFILES) $(PREP) $(RBCONFIG) $(LIBRUBY)
+	@$(MINIRUBY) $(srcdir)/ext/extmk.rb --make="$(MAKE)" --command-output=$@ $(EXTMK_ARGS)
+
 prog: $(PROGRAM) $(WPROGRAM)
 
 miniruby$(EXEEXT): config.status $(LIBRUBY_A) $(MAINOBJ) $(MINIOBJS) $(OBJS) $(DMYEXT)
diff --git a/ext/extmk.rb b/ext/extmk.rb
index 08484aff92..59b451094b 100644
--- a/ext/extmk.rb
+++ b/ext/extmk.rb
@@ -16,6 +16,7 @@ $extlibs = nil
 $extpath = nil
 $ignore = nil
 $message = nil
+$command_output = nil
 
 $progname = $0
 alias $PROGRAM_NAME $0
@@ -239,6 +240,7 @@ end
 
 def parse_args()
   $mflags = []
+  $makeflags = []
 
   opts = nil
   $optparser ||= OptionParser.new do |opts|
@@ -268,11 +270,15 @@ def parse_args()
       if arg = v.first
         arg.insert(0, '-') if /\A[^-][^=]*\Z/ =~ arg
       end
+      $makeflags.concat(v.reject {|arg| /\AMINIRUBY=/ =~ arg}.quote)
       $mflags.concat(v)
     end
     opts.on('--message [MESSAGE]', String) do |v|
       $message = v
     end
+    opts.on('--command-output=FILE', String) do |v|
+      $command_output = v
+    end
   end
   begin
     $optparser.parse!(ARGV)
@@ -528,6 +534,7 @@ void Init_ext _((void))\n{\n#$extinit}
   puts conf
   $stdout.flush
   $mflags.concat(conf)
+  $makeflags.concat(conf)
 else
   FileUtils.rm_f(extinit.to_a)
 end
@@ -544,9 +551,10 @@ Dir.chdir ".."
 unless $destdir.to_s.empty?
   $mflags.defined?("DESTDIR") or $mflags << "DESTDIR=#{$destdir}"
 end
-puts "making #{rubies.join(', ')}"
-$stdout.flush
+message = "making #{rubies.join(', ')}"
 $mflags.concat(rubies)
+$makeflags.uniq!
+$makeflags.concat(rubies)
 
 if $nmake == ?b
   unless (vars = $mflags.grep(/\A\w+=/n)).empty?
@@ -560,7 +568,27 @@ if $nmake == ?b
     vars.each {|flag| flag.sub!(/\A/, "-D")}
   end
 end
-system($make, *sysquote($mflags)) or exit($?.exitstatus)
+if $command_output
+  message = "echo #{message}"
+  cmd = [$make, *sysquote($makeflags)].join(' ')
+  open($command_output, 'wb') do |f|
+    case $command_output
+    when /\.sh\z/
+      f.puts message, "rm -f $0; exec #{cmd}"
+    when /\.bat\z/
+      ["@echo off", message, cmd, "del %0 & exit %ERRORLEVEL%"].each do |s|
+        f.print s, "\r\n"
+      end
+    else
+      f.puts cmd
+    end
+    f.chmod(0755)
+  end
+else
+  puts message
+  $stdout.flush
+  system($make, *sysquote($mflags)) or exit($?.exitstatus)
+end
 
 #Local variables:
 # mode: ruby
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index ed49b5e775..6842a50761 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -1,6 +1,7 @@
 # -*- makefile -*-
 
 SHELL = $(COMSPEC)
+RUNCMD = $(COMSPEC) /c
 MKFILES = Makefile
 NULL = nul
 
@@ -237,6 +238,8 @@ ASMEXT = asm
 
 INSTALLED_LIST= .installed.list
 
+MKMAIN_CMD    = mkmain.bat
+
 !if !defined(WINMAINOBJ)
 WINMAINOBJ    = winmain.$(OBJEXT)
 !endif