facebook/xctool — pull request #418 by vgrichina (2014-09-11 16:57:49+00:00)
Title: Added ability to override Xcode Developer directory.

Setting `DEVELOPER_DIR` variable forces `xctool` to use it instead of
default directory specified by `xcode-select`

This feature is desperately needed in cases when you want to build using different versions of Xcode on the same build box.