[entd] use libchromeos.pc BUG=chromium-os:24959 TEST=build Change-Id: Icbb14cea274501e002d5def4b9551af6eb9cb777 Signed-off-by: Elly Jones <[email protected]> Reviewed-on: https://gerrit.chromium.org/gerrit/14006 Reviewed-by: Mike Frysinger <[email protected]>