support out-of-tree builds

This will allow us to avoid doing a git clone.

BUG=None
TEST=`emerge-x86-alex rootdev` still works

Change-Id: I2515981c5aa426eebecc6333d8ae7b50276ae577
Reviewed-on: https://chromium-review.googlesource.com/175520
Reviewed-by: Liam McLoughlin <lmcloughlin@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed