class Bundler::RubygemsIntegration::MoreFuture

def backport_ext_builder_monitor
  require 'rubygems/ext'
  Gem::Ext::Builder.class_eval do
    if !const_defined?(:CHDIR_MONITOR)
      const_set(:CHDIR_MONITOR, Monitor.new)
    end
    if const_defined?(:CHDIR_MUTEX)
      remove_const(:CHDIR_MUTEX)
      const_set(:CHDIR_MUTEX, const_get(:CHDIR_MONITOR))
    end
  end
end

def ext_lock
  Gem::Ext::Builder::CHDIR_MONITOR
end

def initialize
  super
  backport_ext_builder_monitor
end