Auto merge of #5243 - alexcrichton:more-feature-sync, r=alexcrichton
authorbors <bors@rust-lang.org>
Mon, 26 Mar 2018 06:53:49 +0000 (06:53 +0000)
committerbors <bors@rust-lang.org>
Mon, 26 Mar 2018 06:53:49 +0000 (06:53 +0000)
More effort to only compile Cargo once

Hopefully one final change necessary for rust-lang/rust#49053


Trivial merge