Stable Version to build

[J Decker]

so... I found this.  https://gcc.gnu.org/git/ (or maybe rather  git://
gcc.gnu.org/gcc.git  )
which I have cloned, but when I build this version, there's a checksum
difference in stage 2 and 3 libiberty (and a few other objects).

What might be a good, recent, version to build from?

I also had to make some minor changes to force 'HAVE_PSIGNAL' in libiberty
config.in and opt-suggestions.c failed with selftest.c which generates an
assert about option "-"  (commented out assert)

And maybe it's either of those changes causes the issue because there is
some option in the scripts that is deliberately bad and should generate a
suggestion? (I doubt it).