Back-port into 8.2 an old fix to ensure that BYTE_ORDER gets set

Back-port into 8.2 an old fix to ensure that BYTE_ORDER gets set
correctly on 64-bit Intel Solaris.  Per my proposal yesterday,
8.2 is where we will start considering this platform supported.
While this patch itself could easily go into older branches,
there's not a huge amount of point unless we also make some
significantly-more-invasive changes in the spinlock support.