--- trunk/ext/extmk.rb  (revision 40079)
+++ trunk/ext/extmk.rb  (revision 40080)
@@ -193,19 +193,11 @@
    Logging::logfile 'mkmf.log'
    rm_f makefile
    if conf
-            stdout = $stdout.dup
-            stderr = $stderr.dup
-            unless verbose?
-              $stderr.reopen($stdout.reopen(@null))
-            end
-            begin
+            Logging.open do
+              unless verbose?
+                $stderr.reopen($stdout.reopen(@null))
+              end
               load $0 = conf
-            ensure
-              Logging::log_close
-              $stderr.reopen(stderr)
-              $stdout.reopen(stdout)
-              stdout.close
-              stderr.close
             end
    else
      create_makefile(target)
@@ -235,11 +227,13 @@
         mess = "#{error}\n#{mess}"
       end

-      Logging::message(mess)
+      Logging::message(mess) if Logging.log_opened?
       print(mess)
       $stdout.flush
+      Logging::log_close
       return true
     end
+    Logging::log_close
     args = sysquote($mflags)
     unless $destdir.to_s.empty? or $mflags.defined?("DESTDIR")
       args += [sysquote("DESTDIR=" + relative_from($destdir, "../"+prefix))]
--- trunk/lib/mkmf.rb (revision 40079)
+++ trunk/lib/mkmf.rb (revision 40080)
@@ -310,6 +310,10 @@
       @log.sync = true
     end

+    def self::log_opened?
+      @log and not @log.closed?
+    end
+
     def self::open
       log_open
       $stderr.reopen(@log)