Fix build option : Force ld.gold binary usage

Use the one from chroot instead of the one provided by Chromium third party

BUG=https://crosswalk-project.org/jira/browse/XWALK-1904
Signed-off-by: Baptiste DURAND <baptiste.durand@open.eurogiciel.org>
If those are always passed you can just pass them in the `gyp` call below.