Post-build, post-image, and other build scripts may run some commands in
parallel, for example to parallelize xargs, Makefiles, etc. Export
PARALLEL_JOBS to these scripts so they can enforce the same job limits
that other Buildroot packages use.
Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>