Upgrade of base gcc and libstdc++ to the last GPLv2-licensed revision

Upgrade of base gcc and libstdc++ to the last GPLv2-licensed revision
(rev. 127959 of gcc-4_2-branch).

Resolved GCC bugs:
	c++: 17763, 29365, 30535, 30917, 31337, 31941, 32108, 32112, 32346,
	     32898, 32992
	debug: 32610, 32914
	libstdc++: 33084, 33128
	middle-end: 32563
	rtl-optimization: 33148
	tree-optimization: 25413, 32723
	target: 32218

Tested by:	pointyhat (miwi)
Obtained from:	gcc (gcc-4_2-branch up to rev. 127959)
PR:		gnu/153298, gnu/153959, gnu/154385
MFC after:	1 month