chromeos-base/arc-build-nyc: Add support for multilib

This patch changes the ebuild and pkg-config wrapper installed by it to
properly handle sysroots with multilib enabled. This includes using
multilib-minimal.eclass, patching .pc files from files/ directory with
proper library path and making pkg-config wrapper use correct .pc file
path depending on the $ABI enviornment variable.

BUG=b:36540057
TEST=emerge-reef arc-build-nyc arc-libpciaccess

Change-Id: Idf9103848809958aa85e36388735c196fb873c62
Reviewed-on: https://chromium-review.googlesource.com/488743
Commit-Ready: Tomasz Figa <tfiga@chromium.org>
Tested-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
2 files changed