* README: Add section discussing status of ELF ABI.
        * i370.c: Fix misc spelling mistakes.
        (i370_label_scan): Updated notes, exception handling.
        (i370_function_prolog): Simplify ELF stack handling.
        * i370.h: (FIXED_REGISTERS): Free up r12 for ELF.
        (STACK_GROWS_DOWNWARD): ELF stack grows down.
        (ASM_DECLARE_FUNCTION_NAME): Fix crazy malloc size.
        * i370.md: (movdi): Add notes.
        (floatsidf2): Use stack not rtca for scratch float area.
        (iorsi3): Correct operand constraints.
        * x-oe: Restore TAROUTOPTS which are used by pax.

From-SVN: r29185