--- Modules/FindRuby.cmake.orig	2013-05-18 15:29:53.805033064 +0200
+++ Modules/FindRuby.cmake	2013-05-18 15:30:21.605683563 +0200
@@ -102,7 +102,7 @@
    _RUBY_CONFIG_VAR("sitelibdir" RUBY_SITELIB_DIR)
 
    # vendor_ruby available ?
-   execute_process(COMMAND ${RUBY_EXECUTABLE} -r vendor-specific -e "print 'true'"
+   execute_process(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print 'true' unless Config::CONFIG['vendorarchdir'].nil?"
       OUTPUT_VARIABLE RUBY_HAS_VENDOR_RUBY  ERROR_QUIET)
 
    if(RUBY_HAS_VENDOR_RUBY)