extmk.rb: git rid of post-1.8 features

* ext/extmk.rb (extmake): git rid of post-1.8 features for cross
  compilation.  [ruby-core:50160] [Bug #7439]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Tue Nov 27 04:12:49 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/extmk.rb (extmake): git rid of post-1.8 features for cross
+	  compilation.  [ruby-core:50160] [Bug #7439]
+
 Tue Nov 27 00:13:41 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* thread.c (rb_mutex_trylock, rb_mutex_unlock, mutex_sleep):

ext/extmk.rb

@@ -1,5 +1,5 @@
 #! /usr/local/bin/ruby
-# -*- ruby -*-
+# -*- mode: ruby; coding: us-ascii -*-
 
 $extension = nil
 $extstatic = nil
@@ -42,6 +42,12 @@ $" << "mkmf.rb"
 load File.expand_path("lib/mkmf.rb", srcdir)
 require 'optparse/shellwords'
 
+if defined?(File::NULL)
+  @null = File::NULL
+elsif !File.chardev?(@null = "/dev/null")
+  @null = "nul"
+end
+
 def sysquote(x)
   @quote ||= /os2/ =~ (CROSS_COMPILING || RUBY_PLATFORM)
   @quote ? x.quote : x
@@ -190,7 +196,7 @@ def extmake(target)
             stdout = $stdout.dup
             stderr = $stderr.dup
             unless verbose?
-              $stderr.reopen($stdout.reopen(File::NULL))
+              $stderr.reopen($stdout.reopen(@null))
             end
             begin
               load $0 = conf
@@ -225,7 +231,7 @@ def extmake(target)
 
       mess = "Failed to configure #{target}. It will not be installed.\n"
       if error
-        mess.prepend(error.to_s + "\n")
+        mess = "#{error}\n#{mess}"
       end
 
       Logging::message(mess)