2 files changed, 5 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog
index ad050137c3..991bee7560 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jan  7 23:07:40 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (configuration): backref needs to capture.
+
 Fri Jan  7 21:57:22 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* misc/ruby-mode.el (ruby-mode-variables), misc/ruby-style.el:
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 0b39551033..1a1db54e7f 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -1660,9 +1660,7 @@ VPATH = #{vpath.join(CONFIG['PATH_SEPARATOR'])}
   extconf_h = $extconf_h ? "-DRUBY_EXTCONF_H=\\\"$(RUBY_EXTCONF_H)\\\" " : $defs.join(" ") << " "
   if warnflags = CONFIG['warnflags'] and CONFIG['GCC'] == 'yes' and !$extmk
     # turn warnings into errors only for bundled extensions.
-    warnflags = warnflags.split.map { |flag|
-      flag.gsub(/(?:\A|\s)-Werror=/, '\1-W')
-    }.join ' '
+    warnflags = warnflags.gsub(/(\A|\s)-Werror=/, '\1-W')
   end
   mk << %{
 CC = #{CONFIG['CC']}