elixir-lang/elixir — pull request #1944 by christhekeele (2013-12-18 02:24:44+00:00)
Title: Ignore build artifacts in _build folders.

It's been a while since I've worked on a PR to elixir itself, and I forgot to use `make test` instead of `mix test`, which failed and generated a `_build` folder.

Figured it'd be prudent to go ahead and ignore these to ease the lives of future developers who make the same command-line mishap.