Some TARGET_* flags are being exported in bitbake.conf currently, so
they are impacting all the tasks of a crosssdk recipe even they are
not in use at all.
This can lead a lot of churn when the crosssdk sysroot are shared by
machines while they have defined different TARGET_* flags.
Fix it by overriding with BUILD_* flags.
(From OE-Core rev: 3facbe700a2f28a11620c4954686ed5d5e47a3d9)
Signed-off-by: Ming Liu <peter.x.liu@external.atlascopco.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>