The configuration methods `@conf` are bound to the configuration context, and to the build context::

	@waflib.Configure.conf
	def find_program(ctx):
		pass

	def configure(conf):
		conf.find_program(...)

The object `conf.env` is usually modified during the execution. If several methods have to be called, then
a transaction should be used, for example::

	def configure(conf):
		conf.env.stash()
		try:
			conf.find_program('strip')
			conf.env.append_value('CFLAGS', '-O3')
		finally:
			conf.env.revert()