mozilla/rust — pull request #4089 by BeyondSora (2012-12-01 04:25:40+00:00)
Title: add option validation to configure; now error out on undefined options

This change to configure is for [Issue #4065](https://github.com/mozilla/rust/issues/4065).

Existing `opt` and `valopt` calls now populate a list of valid options.
An validation against user inputs is run after and if an user input does not match any of the options, the build script errors out.