[m-rev.] for review: Fix use of Linux CPU affinity API.

[Peter Wang]

On Wed, 16 May 2018 17:18:20 +1000, Peter Wang <novalazy at gmail.com> wrote:
> 
> The main fix is to retry the sched_getaffinity() call in
> MR_reset_available_cpus(). If that call failed because we provided a
> cpuset that is too small for the kernel, MR_reset_available_cpus() would
> set MR_available_cpus to NULL but leave MR_cpuset_size non-zero,
> leading to a null pointer dereference soon after.

Committed. Will deal with problems if they should arise.

Peter