This makes gas .cfi output to .debug_frame match register numbering
emitted by gcc. md_reg_eh_frame_to_debug_frame follows the ABI,
targets not using it, notably Linux, don't.
* config/tc-ppc.h (md_reg_eh_frame_to_debug_frame): Match current
gcc behaviour.
* config/te-aix.h: New file.
* configure.tgt: Use em=aix for powerpc-aix.