The user needs read and write permissions to SSTATE_DIR, check
whether they have sufficient permissions and if not recommend
use of SSTATE_MIRRORS.
(From OE-Core rev: 0c0c4efbf92bcf0f8942f17c18525a4b4ed1798c)
Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>