 <TT>GC_malloc_many</tt>, so that free lists can be
built, and memory can be cleared, by more than one thread concurrently.
<LI>
Building the collector with -DTHREAD_LOCAL_ALLOC adds support for thread
local allocation.  It does not, by itself, cause thread local allocation
to be used.  It simply allows the use of the interface in 
<TT>gc_local_alloc.h</tt>.
<P>
Memory returned from thread-local allocators is completely interchangeable
with that returned by the standard allocators.  It may be used by other
