Add static gatekeeper library

Add a static library that exports gatekeeper source so that it can
be used in the Gatekeeper TLK task.

Change-Id: I66abcdba860a75c29bdc5a67ad8f0aee5de872cf
(cherry picked from commit 9be92ed1b5a470cb824516a9b950256a138533f8)
1 file changed