diff --git a/ChangeLog b/ChangeLog
index f183534dc9..e267e6dc0e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Nov 11 08:20:56 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* Makefile.in (OUTFLAG): keep trailing spaces.  [ruby-dev:27666]
+
+	* mkconfig.rb: substitution refereces added.
+
 Fri Nov 11 07:39:49 2005  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 
 	* configure.in: undef HAVE_LINK on BeOS. (link(2) always returns
diff --git a/Makefile.in b/Makefile.in
index ee0a1275e9..6dfeb1c38d 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -30,7 +30,8 @@ RDOCTARGET = @RDOCTARGET@
 EXTOUT = @EXTOUT@
 RIDATADIR = $(DESTDIR)$(datadir)/ri/$(MAJOR).$(MINOR)/system
 
-OUTFLAG = -o 
+empty =
+OUTFLAG = @OUTFLAG@$(empty)
 CFLAGS = @CFLAGS@ @XCFLAGS@ @ARCH_FLAG@
 CPPFLAGS = -I. -I$(srcdir) @CPPFLAGS@
 LDFLAGS = @STATIC@ $(CFLAGS) @LDFLAGS@
diff --git a/mkconfig.rb b/mkconfig.rb
index 4a8062e9fa..0060b608b3 100644
--- a/mkconfig.rb
+++ b/mkconfig.rb
@@ -16,10 +16,10 @@ unless File.directory?(dir = File.dirname(rbconfig_rb))
 end
 
 version = RUBY_VERSION
-rbconfig_rb_tmp = rbconfig_rb + '.tmp'
-config = open(rbconfig_rb_tmp, "w")
-$orgout = $stdout.dup
-$stdout.reopen(config)
+def (config = "").write(arg)
+  concat(arg.to_s)
+end
+$stdout = config
 
 fast = {'prefix'=>TRUE, 'ruby_install_name'=>TRUE, 'INSTALL'=>TRUE, 'EXEEXT'=>TRUE}
 print %[
@@ -120,10 +120,13 @@ print <<EOS
     val.gsub!(/\\$\\$|\\$\\(([^()]+)\\)|\\$\\{([^{}]+)\\}/) do |var|
       if !(v = $1 || $2)
 	'$'
-      elsif key = config[v]
+      elsif key = config[v = v[/\\A[^:]+(?=(?::(.*?)=(.*))?\\z)/]]
+	pat, sub = $1, $2
 	config[v] = false
 	Config::expand(key, config)
 	config[v] = key
+	key = key.gsub(/\#{Regexp.quote(pat)}(?=\\s|\\z)/n) {sub} if pat
+	key
       else
 	var
       end
@@ -136,17 +139,19 @@ print <<EOS
 end
 CROSS_COMPILING = nil unless defined? CROSS_COMPILING
 EOS
-$stdout.flush
-$stdout.reopen($orgout)
-config.close
-if $timestamp and
-   File.exist?(rbconfig_rb) and
-   FileUtils.compare_file(rbconfig_rb, rbconfig_rb_tmp)
-  puts "#{rbconfig_rb} unchanged"
-  File.unlink(rbconfig_rb_tmp)
-else
-  puts "#{rbconfig_rb} updated"
-  File.rename(rbconfig_rb_tmp, rbconfig_rb)
+
+$stdout = STDOUT
+mode = IO::RDWR|IO::CREAT
+mode |= IO::BINARY if defined?(IO::BINARY)
+open(rbconfig_rb, mode) do |f|
+  if $timestamp and f.stat.size == config.size and f.read == config
+    puts "#{rbconfig_rb} unchanged"
+  else
+    puts "#{rbconfig_rb} updated"
+    f.rewind
+    f.truncate(0)
+    f.print(config)
+  end
 end
 if String === $timestamp
   FileUtils.touch($timestamp)