Add lorgnette as an optional build target

Include lorgnette behind a use flag.

CQ-DEPEND=CL:191442
BUG=chromium:356263
TEST=test USE=lorgnette emerge-${BOARD} platform2
using upcoming changes to platform2 ebuild.

Change-Id: I9768faf0109d50b121f653fc6976efd6c7717a1a
Reviewed-on: https://chromium-review.googlesource.com/191478
Reviewed-by: Mike Frysinger <[email protected]>
Tested-by: Paul Stewart <[email protected]>
Commit-Queue: Paul Stewart <[email protected]>
2 files changed