Make clang host compiler use ${CHOST}.

Currently the host clang compiler is just 'clang'.  This CL makes
it 'x86_64-pc-linux-gnu-clang' ie. ${CHOST}-clang.

BUG=None
CQ-DEPEND=CL:489563
TEST=Testing in chromiumos-sdk and other trybots.

Change-Id: I2fb94f7c9fb5473dc6b10de788c5d72983fd597c
Reviewed-on: https://chromium-review.googlesource.com/503509
Commit-Ready: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed