Auto merge of #2365 - japaric:env-gt-config, r=alexcrichton
authorbors <bors@rust-lang.org>
Fri, 12 Feb 2016 23:03:56 +0000 (23:03 +0000)
committerbors <bors@rust-lang.org>
Fri, 12 Feb 2016 23:03:56 +0000 (23:03 +0000)
This patches fixes the precedence in these cases:

- CARGO_TARGET_ROOT is now preferred over build.target-dir
- RUSTC is now preferred over build.rustc
- RUSTDOC is now preferred over build.rustdoc

r? @alexcrichton


Trivial merge