cros-constants: allow build systems to override this

If we want to build outside of the chroot, we need to be able to point
the root source code somewhere else.

BUG=b:20895978
TEST=precq passes

Change-Id: Ifeab2d60b29a06c0b84d0a6e113d0bfe5eed19a5
Reviewed-on: https://chromium-review.googlesource.com/275109
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed
tree: 8cb6316f9fa04637416c5aed22e399fb9dba6565
  1. eclass/
  2. metadata/
  3. profiles/
  4. PRESUBMIT.cfg