Index: b/Modules/FindRuby.cmake
===================================================================
--- a/Modules/FindRuby.cmake
+++ b/Modules/FindRuby.cmake
@@ -110,7 +110,7 @@ if(RUBY_EXECUTABLE  AND NOT  RUBY_VERSIO
    _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 RbConfig::CONFIG['vendorarchdir'].nil?"
       OUTPUT_VARIABLE RUBY_HAS_VENDOR_RUBY  ERROR_QUIET)
 
    if(RUBY_HAS_VENDOR_RUBY)