Require builder before fast_xs so we don't tickle its over-eager String#to_xs collision check

activesupport/lib/active_support/vendor.rb

@@ -6,6 +6,7 @@ begin
 rescue Gem::LoadError
   $:.unshift "#{File.dirname(__FILE__)}/vendor/builder-2.1.2"
 end
+require 'builder'
 
 begin
   gem 'xml-simple', '~> 1.0.11'
@@ -31,4 +32,4 @@ end
 # rescue Gem::LoadError
   $:.unshift "#{File.dirname(__FILE__)}/vendor/i18n-0.0.1"
   require 'i18n'
-# end
+# end