Test for _AM29K and _IBMR2, not ___AM29K__ and ___IBMR2__.

Test for _AM29K and _IBMR2, not ___AM29K__ and ___IBMR2__.

(arm umul_ppmm): New definition.
(clipper umul_ppmm, smul_ppmm, __umulsidi3): New definitions.
(hppa count_leading_zeros): New definition.
(i960 umul_ppmm, __umulsidi3): New definitions.
(mc68000 umul_ppmm): Use %. before size suffixes.
(mc88110 umul_ppmm, udiv_qrnnd): Rewrite.
(mc88000): Get UMUL_TIME and UDIV_TIME right.
(mips): Get UMUL_TIME right.
(ns32000 umul_ppmm): New definition.
(ns32000 udiv_qrnnd): Rename from bogus div_qrnnd, rewrite.
(powerpc umul_ppmm, smul_ppmm): New definitions.
(_IBMR2/powerpc add_ssaaaa, sub_ddmmss): Improve.
(pyr umul_ppmm): Fix typo.
(sparc add_ssaaaa, sub_ddmmss): Match constant 0 for all inputs.
(vax sdiv_qrnnd): New definition.

From-SVN: r7629