MFC r275533:

Sync with Illumos.  This have no effect to FreeBSD.

Illumos issue:
    5100 sparc build failed after 5004

MFC after:	2 weeks
MFV r275534:

Sync with Illumos.  This have no effect to FreeBSD.

Illumos issue:
    5285 pass in cpu_pause_func via pause_cpus

MFC after:	2 weeks