Basic support for 64-bit Darwin.

Basic support for 64-bit Darwin.

        * config/darwin.c (macho_indirect_data_reference): Add DImode case.
        (machopic_legitimize_pic_address): Similarly, plus use Pmode
        instead of SImode.
        * config/rs6000/darwin.h (PTRDIFF_TYPE): Be "long int" if 64-bit.
        (TARGET_OS_CPP_BUILTINS): Add 64-bit preprocessor macro.
        (SUBTARGET_SWITCHES): Add -m32 and -m64 flags.
        (SUBTARGET_OVERRIDE_OPTIONS): Require 64-bit processor if -m64.
        (PROCESSOR_DEFAULT64): Define.
        * config/rs6000/darwin.md: New file, patterns specific to 64-bit
        Darwin.
        * config/rs6000/rs6000.md: Include darwin.md.
        (builtin_setjmp_receiver): Add DImode case.
        * config/rs6000/rs6000.c (TARGET_ASM_UNALIGNED_DI_OP): Define for
        Darwin.
        (TARGET_ASM_ALIGNED_DI_OP): Ditto.
        (rs6000_emit_move): Add DImode case to Darwin bits.
        (machopic_output_stub): Use .quad if 64-bit.
        * invoke.texi: Document -m32 and -m64.

From-SVN: r86070