x-rs6000: New file.

x-rs6000: New file.

        * config/rs6000/x-rs6000: New file.
        * config/rs6000/darwin.h (CC1_SPEC): Add cc1_cpu.
        * config/rs6000/rs6000.h (EXTRA_SPECS): Add cc1_cpu.
        (EXTRA_SPEC_FUNCTIONS): Define.
        (HAVE_LOCAL_CPU_DETECT): Define.
        (CC1_CPU_SPEC): Define.
        * config/rs6000/driver-rs6000.c: New file.
        * config/rs6000/aix.h (CC1_SPEC): Define.
        * config/rs6000/sysv4.h (CC1_SPEC): Add cc1_cpu.
        * config.host: Add x-rs6000 to host_xmake_file if host and target
        are rs6000 or powerpc.

From-SVN: r127304