diff --git a/ChangeLog b/ChangeLog
index be85a65f60..a02c4238fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Oct 31 12:27:52 2008  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
+
+	* spec/default.mspec: supports that the build directory != srcdir.
+
 Fri Oct 31 11:35:38 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* encoding.c (rb_enc_set_default_internal): no alias "internal" if
diff --git a/spec/default.mspec b/spec/default.mspec
index e4b9dae523..a018b4020c 100644
--- a/spec/default.mspec
+++ b/spec/default.mspec
@@ -7,11 +7,14 @@ class MSpecScript
     spec/rubyspec/1.9/library
   ]
 
-  srcdir = File.expand_path(File.join(File.dirname(__FILE__), '..'))
-  config = proc{|name| `#{srcdir}/miniruby -I#{srcdir} -rrbconfig -e 'print Config::CONFIG["#{name}"]'`}
+  builddir = File.expand_path(File.join(File.dirname(__FILE__), '..'))
+  srcdir = ENV['SRCDIR']
+  srcdir ||= $1 if File.read("#{builddir}/Makefile")[/^\s*srcdir\s*=\s*(.+)/i]
+  srcdir ||= builddir
+  config = proc{|name| `#{builddir}/miniruby -I#{srcdir} -rrbconfig -e 'print Config::CONFIG["#{name}"]'`}
 
   # The default implementation to run the specs.
-  set :target, File.join(srcdir, "miniruby#{config['exeext']}")
+  set :target, File.join(builddir, "miniruby#{config['exeext']}")
   set :flags, %W[
     -I#{srcdir}/lib
     -I#{srcdir}/#{config['EXTOUT']}/common