Profiling broken on powerpc-ibm-aix4.1.4.0

[David Edelsohn]

	The problem is that with the scheduled prologue, GCC is scheduling
instructions around the call to the profiler without treating it as a
normal call with normal volatile register issues.  The AIX profile
subroutine is using some volatile scratch registers but the backend does
not "see" the call and does not preserve them or avoid moving instructions
across that call.

	Geoff probably has better insight into how to handle this
situation properly.

David