diff --git a/ChangeLog b/ChangeLog
index 87cde446b6..f7e23c6c95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jan 11 10:24:03 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/rdoc/options.rb ():
+
 Fri Jan 11 09:59:05 2008  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* ext/nkf/nkf-utf8/nkf.c: update to r1.163.
diff --git a/lib/rdoc/options.rb b/lib/rdoc/options.rb
index 02ee75ee0c..078635121c 100644
--- a/lib/rdoc/options.rb
+++ b/lib/rdoc/options.rb
@@ -567,7 +567,7 @@ Usage: #{opt.program_name} [options] [names...]
   # Windows.
 
   def check_diagram
-    return if RUBY_PLATFORM =~ /mswin/
+    return if RUBY_PLATFORM =~ /mswin|cygwin|mingw|bccwin/
 
     ok = false
     ver = nil