Original commit message from CVS:
- Fix cothread pointers and allocation so full 2M stack space available:
- Double maximums to use full stack space:
- COTHREAD_STACKSIZE = 16k
- COTHREAD_MAXTHREADS = 128
- cothread changes only verified on x86
- cothread_create returns NULL if nthreads == MAXTHREADS though not yet handled by gstschedule caller