Add some unspeakable hackery to the tree under #ifdef ia64 to work
around limitations in the ia64 kernel stack handling code. Basically
preallocate a bunch of threads (and hence kstacks) while contigmalloc()
still works, and never free them back to the general memory pool. After
the system has been running for a while, contigmalloc() eventually fails
at a critical momemt and panics the system.