add a LIBSUBDIR setting to control /usr/lib path

Don't hardcode /usr/lib all the time as that is wrong on many systems
(like x86_64).  Add a variable the ebuild can set to the right place.

BUG=chromium:874977
TEST=building for stout installs libs into /usr/lib64 now

Change-Id: Icb058498a354a1914be640638a9983aa53bcfe67
Reviewed-on: https://chromium-review.googlesource.com/c/1391968
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
3 files changed