Respect PKG_CONFIG variable if set in the environment.

This is required for the new cross-compilation support using pkg-config
wrappers instead of changing the pkg-config files themselves.

BUG=none
TEST=emerge-arm-generic with and without pkg-config wrappers

Change-Id: I46d17ccea3d367796ada548822eec9dd8dc104fe
Reviewed-on: http://gerrit.chromium.org/gerrit/1438
Reviewed-by: Daniel Erat <derat@chromium.org>
Tested-by: Diego Elio Pettenò <flameeyes@chromium.org>
1 file changed