The host-build of libselinux requires libsepol/host.
Add the libsepol/host to HOST_BUILD_DEPENDS to allow build on hosts
which don't have libsepol installed.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
(cherry picked from commit 0d3850dc5af4896ab3679dc4d8ef9a664e5e705f)