re: NetBSD/vax 11.0_RC2

i haven't yet gotten far figuring out the real hang that
gcc 12 gimple-match.cc triggers, but i have found that
before upstream broke it into 10 files, they reduced the
size of the output significantly, and it seems to allow
compiling this file with 256mb ram in simh.

   https://www.netbsd.org/~mrg/nb-gcc12-genmatch1.diff

this combines 4 mainline GCC changes that reduce the
generated file to about 2/3rds the original.

i've been testing this change on netbsd-11's GCC 12 for
several platforms and it seems not to introduce any
failures for me -- i've also been testing it in pkgsrc
gcc12 on arm64, powerpc, and amd64 so far.


i am curious what others find with this patch.  it is for
netbsd-11 src/external/gpl3/gcc/dist/gcc or, in current,
gcc.old/dist/gcc (only really relevant for m68k, sh3, and
alpha who are still using GCC 12 there.)

(this problem isn't in -current's GCC 14, since the above
patch plus something to split the output into 10 files is
in that tree already, and it's better from a total ram
size / total paralellism POV.)


.mrg.