PATCH: Add sysdeps/x86_64/x32/tls.h

[Roland McGrath]

That is OK but it would be better with a comment explaining why it's
necessary.  You only mentioned the need to use a register temporary
because an indirect call would load too much from the pointer, but
it also matters that the load of the argument register would load
too much and have other stuff in the high bits rather than the
zero-extension that you do here.  The comment should mention that
both issues matter.


Thanks,
Roland