* sysdeps/mach/powerpc/machine-sp.h: New file.
* sysdeps/mach/powerpc/sysdep.h: New file.
* sysdeps/mach/powerpc/thread_state.h: New file.
* sysdeps/mach/hurd/i386/Makefile: File removed; crt0.o rules moved ...
* sysdeps/mach/hurd/Makefile: ... to here. For the time being, we can
expect to need the same thing on every platform.
* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h: File moved ...
* sysdeps/generic/sys/ucontext.h: ... to replace this one.
