newlock2 is too raw for even x86 architectures. It's not applied to
all architectures. It breaks threading because of bugs it introduces
into libpthread.

Please revert it, fix at least:

1) Compiles and passes simple tests on all archs
2) Retains m:n support for uniprocessor as an option
3) a reasonable amount of pthread testing

before reapplying it.

Based on a lot of experience with this sort of change, it's my opinion
that you'll get to a stable newlock faster that way than by dropping
the changes into current and trying to fix them there.