make kernel linker work in user space as well
we can't call clts in user - return right away from fpuinit
give an arbitrary (small) number for physmem to allow us to initialize correctly
add shim userret, GC fork_return, and add kernel-only cpu_fork
changes to link in kern_fork.c
remove pthread references
initialize our uma_page_slab_hash and remove unneeded proctree_lock initialization
simple workarounds to let us make it to the swapper
make pmap_qremove a no-op for now
add kern_fork.c and disable inlining and register optimizations for now