(ABI_64BIT): Delete.
(TARGET_OPTIONS, INITIAL_ELIMINATION_OFFSET, GO_IF_LEGITIMATE_ADDRESS,
CONSTANT_ADDRESS_P, LEGITIMATE_CONSTANT_P, LEGITIMIZE_ADDRESS,
ASM_OUTPUT_ADDR_DIFF_ELT): Modify.
(enum mips_abi_type, SUBTARGET_TARGET_OPTIONS): Define.
(mips_abi, mips_abi_string): Declare.

From-SVN: r12131