MFC r226422, r227241, r228063, r228697, r228698, r228701, r234310, r234850,
r250226, r250926.

This brings m4 up to date with the version in head and fixes the eval
command when called with a 2nd and 3rd argument.  The only differences
remaining are related to the updated flex and byacc in head.

PR:		bin/166994
MFC	r258081, r258138, r258143, r258179, r258157, r258204, 258205,
	r258206, r258207, r258321

This is a series of commits inspired on Google's gcc-4.2.1 for
Android that were taken from the gcc pre-4.3 under the GPLv2.

gcc: Backport fixes for -W parentheses in C++
	This fixes GCC 19564.
gcc: merge rs6000 change from FSF pre-gcc43
	Don't set MASK_PPC_GFXOPT for 8540 or 8548.
Merge vrp-tree fix from gcc-4.3
	Fix missed conversion from / to >> (GCC PR32521)
Merge in GCCr120505 to include definition of TREE_OVERFLOW_P
gcc: warn about integer overflow in constant expressions in the C++ frontend.
gcc: Add a new option -Wvla to warn variable length array.
libcpp: preprocessor speedup patches from upstream gcc.
gcc: add femit-struct-debug support to reduce Reduce dwarf debug size
gcc: Fix postreload-gcse treatment of call-clobbered registers.
gcc: Record some previous commits in the ChangeLog.gcc43 file.
MFC r258712;

libcpp: fix an underflow.

Similar fix seen in Apple's gcc42.

Obtained from:	OpenBSD (Rev 1.2)
MFC after:	2 weeks
mtest(8): use correct macro in mdoc

	The An macros is used for authors while the Ar macro is used for arguments.
	AFAIK mcast-addr and ifname are not authors.

PR:		docs/184649
MFC r244673:

Fix the __glibcxx_min and __glibcxx_max macros for a signed wchar_t.

This seems to be needed by newer compilers.
[automated] Merge in upstream-github/stable/9