remove a few warnings
add gcc 4.6+ leaf function annotation
add getcontext and setcontext for i386 and x86_64
  /* do not restore gs because it's thread-specific */
  add getcontext, setcontext, makecontext, swapcontext (i386 and x86_64 only for now)
  add implementation of hsearch and friends
cvsimport

Conflicts:
	lib/nice.c
	lib/stackgap.c