ffmpeg: Fix pkg-config usage

http://crrev.com/c/1715466 blocks direct call of pkg-config,
use tc-getPKG_CONFIG to get pkg-config tool.

Since ffmpeg is uprev to new version and chromium version
of ebuild does not exist,so applied patch in upstream 9999
ebuild.
Cheery pick https://github.com/gentoo/gentoo/commit/bb91cfbdd67d5d5336de6d9d382f9ac9417b4cdc

BUG=chromium:985180
TEST=emerge-<board> ffmpeg

Change-Id: I3de4c37e0f560426b82c490c91eebc2611ca26cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2334238
Tested-by: Abhishek Kumar <abhishek4.kumar@intel.com>
Commit-Queue: Abhishek Kumar <abhishek4.kumar@intel.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed