* rs6000-aix-tdep.c: Include "regcache.h", "regset.h", and
"gdb_string.h".
(rs6000_aix32_reg_offsets, rs6000_aix64_reg_offsets): New variables.
(rs6000_aix_supply_regset, rs6000_aix_collect_regset): New functions.
(rs6000_aix32_regset, rs6000_aix64_regset): New variables.
(rs6000_aix_regset_from_core_section): New function.
(rs6000_aix_init_osabi): Register it.
(_initialize_rs6000_aix_tdep): Register GDB_OSABI_AIX osabi and
sniffer for bfd_arch_powerpc as well as bfd_arch_rs6000.
* rs6000-nat.c (CoreRegs): Do not define type.
(fetch_core_registers, rs6000_core_fns): Remove.
(_initialize_core_rs6000): Do not register it. Rename to ...
(_initialize_rs6000_nat): ... this.
* Makefile.in (rs6000-aix-tdep.o): Update dependencies.