various updates to build native GCC 12.

- for usr.bin, build libcody and link it into cc1*plus
- move makefile code for auto-build.h and version.h (was gcov-iov.h)
into makefile fragment to share them. (XXX probably best to only do
this in one place, but that's a future step.)
- many updates to handle the .c -> .cc renames
- build some x86 files with -msse2
- bump shlib versions for libgomp and libstdc++v3
- fix MKGCCCMDS=no builds
- updates for new rtl-ssa subdir
- use -std=gnu++11 for various places
- define TARGET_MACHINE and HOST_MACHINE for some places
- avoid a .BEGIN rule that writes to missing obj (ie src) sometimes

cleanups still needed:
- remove a bunch of commented -Wno* that don't seem to be needed anymore
- leave or remove various vax-specific -O0s that should no longer be
necessary for the vax-gcc port
- some "XXXGCC12" that should be may be fixable or converted to using our
standard ${CC_...} warnings (but may need to remain, in which case the
XXXGCC12 marker will be removed.)

with these, and a few other changes around the tree, i've able to build
gcc12 releases for several ports that seem to work (arm64, sparc, amd64,
i386 at least so far, have run, several others have built.)

port reachover framework to GCC 9.

fix the cleanfiles for hooks mechanism

branches: 1.1.4; 1.1.8; 1.1.28;
merge GCC 4.8 build.

port reachover framework to GCC 9.

fix the cleanfiles for hooks mechanism

branches: 1.1.4; 1.1.8; 1.1.28;
merge GCC 4.8 build.

fix the cleanfiles for hooks mechanism

branches: 1.1.4; 1.1.8; 1.1.28;
merge GCC 4.8 build.

branches: 1.1.4; 1.1.8;
merge GCC 4.8 build.

Rebase to HEAD as of a few days ago.

file Makefile.hooks was added on branch tls-maxphys on 2014-08-19 23:53:09 +0000

sync with head.

for a reference, the tree before this commit was tagged
as yamt-pagecache-tag8.

this commit was splitted into small chunks to avoid
a limitation of cvs. ("Protocol error: too many arguments")

file Makefile.hooks was added on branch yamt-pagecache on 2014-05-22 16:53:12 +0000