gcc: another round of merges from the gcc pre-43 branch.

Bring The following revisions from the gcc43 branch[1]:

118360, 118361, 118363, 118576, 119820,
123906, 125246, and 125721.

They all have in common that the were merged long ago
into Apple's gcc and should help improve the general
quality of the compiler and make it easier to bring
new features from Apple's gcc42.

For details please review the additions to the files:
gcc/ChangeLog.gcc43
gcc/cp/ChangeLog.gcc43 (new, adds previous revisions)

Reference:
[1] http://gcc.gnu.org/viewcvs/gcc/trunk/?pathrev=126700

Obtained from:	gcc pre4.3 (GPLv2) branch
MFC after:	3 weeks
libstdc++: merge non-abi changes from Apple's developer tools

Take some changes from Apple's Developer Tools 4.0 [1]:

block.patch
emergency-buffer-reduction.patch
test_cleanup.patch

vector_copy_no_alloc.patch
	problem/6473222 copy-constructing a std::vector	from an
	empty std::vector calls malloc

2008-10-27  Howard Hinnant
stl_tree_system_header.patch
	Added #pragma GCC system_header to stl_tree.h.
copy_doc.patch
	Corrected documentation concerning copy in stl_algobase.h.
string_compare.patch
	Fixed basic_string.h, basic_string.tcc, incorrect 64bit to
	32bit narrowing.

Reference:

[1] http://opensource.apple.com/source/libstdcxx/libstdcxx-39/patches-4.2.1/

Obtained from:	Apple
MFC after:	1 month