I am trying to build pthread support into Python using the pkg
system.  I tried the various methods explained in mk/pthread.buildlink.mk
to build against pth and unproven-pthreads but am having trouble.

1) .include "../../mk/pthread.buildlink.mk"

Just using the default pth - doesn't build as it can't find the
pthread libraries even though the .buildlink/lib directory is
pointing in what appears to be the correct location:

libpth.a -> /usr/pkg/lib/libpth.a
libpth.so -> /usr/pkg/lib/libpth.so
libpth.so.14 -> /usr/pkg/lib/libpth.so.14
libpth.so.14.21 -> /usr/pkg/lib/libpth.so.14.21
libpthread.a -> /usr/pkg/lib/libpthread.a
libpthread.so -> /usr/pkg/lib/libpthread.so
libpthread.so.14 -> /usr/pkg/lib/libpthread.so.14
libpthread.so.14.21 -> /usr/pkg/lib/libpthread.so.14.21
libz.a -> /usr/lib/libz.a
libz.so -> /usr/lib/libz.so
libz.so.0 -> /usr/lib/libz.so.0
libz.so.0.2 -> /usr/lib/libz.so.0.2
 
2) attempt to specify unproven-pthreads

I don't see a way, using any of _PKG_PTHREAD, PTHREAD_TYPE,
PTHREAD_OPTS (or .include "../../devel/unproven-pthreads/buildlink.mk")
to have .buildlink point at the correct libraries.  They always
point at the pth stuff.

Incidentally, this method builds using the uproven-pthreads compiler
- but against the pth libraries which core-dump when I try to use
them.

What is the correct way to build this?

Thanks