mkrunnable.rb: build_os

* tool/mkrunnable.rb: see build_os instead of target arch for
  cross-compiling.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36673 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,7 @@
-Thu Aug  9 23:46:47 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Thu Aug  9 23:46:51 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* tool/mkrunnable.rb: see build_os instead of target arch for
+	  cross-compiling.
 
 	* configure.in (MINIRUBY): use real path for include path.
 

tool/mkrunnable.rb

@@ -34,7 +34,7 @@ end
 
 alias ln_dir_safe ln_safe
 
-if /mingw|mswin/ =~ RUBY_PLATFORM
+if /mingw|mswin/ =~ RbConfig::CONFIG["build_os"]
   extend Mswin
 end