diff --git a/ChangeLog b/ChangeLog
index 4583026b47..58a44b03cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri May 27 16:32:04 2005  WATANABE Hirofumi  <eban@ruby-lang.org>
+
+	* lib/mkmf.rb: use the semicolon as the path separator
+	  in the environment of MSYS.  fixed: [ruby-dev:26232]
+
 Thu May 26 06:08:11 2005  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 
 	* ext/tk/lib/tk.rb: add shortcut-methods of tk_call + tk_split_list
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 184b9b3269..3c61eccbda 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -834,11 +834,15 @@ end
 def configuration(srcdir)
   mk = []
   vpath = %w[$(srcdir) $(topdir) $(hdrdir)]
-  if !CROSS_COMPILING && CONFIG['build_os'] == 'cygwin' && CONFIG['target_os'] != 'cygwin'
-    vpath.each {|p| p.sub!(/.*/, '$(shell cygpath -u \&)')}
-  end
-  if !CROSS_COMPILING && CONFIG['build_os'] == 'msdosdjgpp'
-    CONFIG['PATH_SEPARATOR'] = ';'
+  if !CROSS_COMPILING
+    case CONFIG['build_os']
+    when 'cygwin'
+      if CONFIG['target_os'] != 'cygwin'
+        vpath.each {|p| p.sub!(/.*/, '$(shell cygpath -u \&)')}
+      end
+    when 'msdosdjgpp', 'mingw32'
+      CONFIG['PATH_SEPARATOR'] = ';'
+    end
   end
   mk << %{
 SHELL = /bin/sh