[Gm2] GNU libpth removed now from master

[Gaius Mulley]

Hi,

I've git pushed changes to the master branch to remove libpth and use
libpthread instead.  The PIM SYSTEM coroutines and ISO SYSTEM coroutines
have been re-implemented - there is still a bug in IOTRANSFER which I'm
still working on.  Hopefully this new implementation will be more
portable and it is one of the few times when a git push decreases the
total lines of code for the project :-)


regards,
Gaius