 <TT>gc_locks.h</tt>
<P>
The easiest case is probably a new pthreads platform
on which threads can be stopped
with signals.  In this case, the changes involve:
<OL>
<LI>Introducing a suitable <TT>GC_</tt><I>X</i><TT>_THREADS</tt> macro, which should
be automatically defined by <TT>gc_config_macros.h</tt> in the right cases.
It should also result in a definition of <TT>GC_PTHREADS</tt>, as for the
existing cases.
<LI>For GC7+, ensuring that the <TT>atomic_ops</tt> package at least
minimally supports the plat