Define AGL_META_CLANG in the agl-demo template to pull in
meta-clang, as it seems required to avoid dependency errors from
the uutils-coreutils recipe in meta-oe when selinux is present in
DISTRO_FEATURES. It may be worthwhile investigating further and
discussing with upstream, as this seems a bit unusual.
Bug-AGL: SPEC-4578
Change-Id: Ib8ac8d02b86491bded5463670c87d12a8e66df6a Signed-off-by: Scott Murray <scott.murray@konsulko.com>