--- Modules/FindRuby.cmake.orig	2012-11-02 14:34:25.497624983 +0100
+++ Modules/FindRuby.cmake	2012-11-02 14:36:22.893205108 +0100
@@ -93,7 +93,7 @@
    _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)