def METHOD_NAME(self):
	"""
	Add required variables for ruby extensions
	"""
	self.install_path = '${ARCHDIR_RUBY}'
	self.uselib = self.to_list(getattr(self, 'uselib', ''))
	if not 'RUBY' in self.uselib:
		self.uselib.append('RUBY')
	if not 'RUBYEXT' in self.uselib:
		self.uselib.append('RUBYEXT')