imageburner: Calculate gmock/gtest library dependencies programatically

(gmock/gtest doesn't generate pkg-config metadata, calculating lib
 dependencies this way makes it easier to upgrade gmock/gtest packages.)

BUG=chromium:211445
TEST=build and run tests for package using gtest 1.6

Change-Id: I11e552297e5d5b99ee8387b0388b1f51ffb0d616
Reviewed-on: https://gerrit.chromium.org/gerrit/46421
Reviewed-by: <tbarzic@google.com>
Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Tested-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: Gaurav Shah <gauravsh@chromium.org>
1 file changed