initialization problem w/ thread-specific .tbss data on i386

[Phil Shafer]

Dimitry Andric writes:
>Aha, this might very well be the root cause for
>https://bugs.freebsd.org/227552, could you please have a look at that?

Yes, this looks like the same issue.  I've added my email as a
comment to that PR.

Given the size of xo_handle_t (328 bytes), I'm not sure this is an
alignment issue.  Most of the 328 bytes are polluted.

Thanks,
 Phil