[Gm2] pth and gm2

[Gaius Mulley]

Hi,

I've uploaded some changes to gm2 which include:

   o  many bug fixes to h2def
   o  an example of a gm2 module utilizing -lpth (GNU Pthreads)
      located in: gm2/examples/pthreads.
      The example is a rewrite of test_select.c from the pth
      source release. The DEFINITION MODULE FOR "C" was created
      by h2def (90%) and the last 10% by hand.
   o  made all identifiers automatically export unqualified when inside a
      DEFINITION MODULE FOR "C" (providing an EXPORT QUALIFIED was not seen)

Finishing the first cut of pth.def should allow progress to continue
on the ISO COROUTINES and PIM SYSTEM routines, TRANSFER and
NEWPROCESS.

Gaius