diff --git a/ChangeLog b/ChangeLog
index d7d66d9289..855a3854ae 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Sep  9 13:38:56 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* tool/extlibs.rb (do_patch): let "patch" command change the
+	  working directory and open the patch file there, instead of
+	  spawn options, so that proper error message will be shown by the
+	  command not just "chdir" or "open".
+
 Wed Sep  9 11:33:05 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* common.mk (update-gems): use BASERUBY instead of RUNRUBY.
diff --git a/tool/extlibs.rb b/tool/extlibs.rb
index 09db055983..6323d8fdcd 100755
--- a/tool/extlibs.rb
+++ b/tool/extlibs.rb
@@ -70,7 +70,7 @@ def do_patch(dest, patch, args)
     $stdout.puts "applying #{patch} under #{dest}"
     $stdout.flush
   end
-  Process.wait(Process.spawn("patch", *args, in: File.join(dest, patch), chdir: dest))
+  Process.wait(Process.spawn("patch", "-d", dest, "-i", patch, *args))
   $?.success? or raise "failed to patch #{patch}"
 end