abi64.h (LONG_MAX_SPEC): Check MIPS_ABI_DEFAULT and TARGET_DEFAULT, and define __LONG_MAX__ appropriately.

        * abi64.h (LONG_MAX_SPEC): Check MIPS_ABI_DEFAULT and TARGET_DEFAULT,
        and define __LONG_MAX__ appropriately.  Add support for -mabi=X,
        -mlong64, and -mgp{32,64} options.
        * mips.c (mips_abi): Change type to int.
        * mips.h (enum mips_abi_type): Delete.
        (ABI_32, ABI_N32, ABI_64, ABI_EABI): Define as constants.
        (mips_abi): Change type to int.

From-SVN: r17229