mesa: fix mesa_populate_packages() when dri is disabled
When compiling mesa, if dri is disabled in PACKAGECONFIG, or if the list of DRI
drivers is empty, it will cause populate_package to fail, because it can't find
- rightfully - the directory for the DRI drivers. This patch checks that the
directory indeed exists before trying to get a list of the files in it
[ use oe.path.join instead of + - RB ]
Signed-off-by: Herve Jourdain <herve.jourdain@neuf.fr> Signed-off-by: Ross Burton <ross.burton@intel.com>
