(ROUND_TYPE_ALIGN): Align XFmode scalars at 128 bit boundaries.
(ROUND_TYPE_SIZE): Round up the size of XFmode objects to 128 bits.
(CONST_DOUBLE_OK_FOR_LETTER_P): Use CONST0_RTX and CONST1_RTX
so that all FP modes are recognized.
(ASM_OUTPUT_LONG_DOUBLE): Define.

From-SVN: r9739