Going for "all green" buildfarm results

I've been making another pass over getting rid of buildfarm failures.
The remaining ones I see at the moment are:

firefly HEAD: intermittent failures in the stats test.  We seem to have
fixed every other platform back in January, but not this one.

kudu HEAD: one-time failure 6/1/06 in statement_timeout test, never seen
before.  Is it possible system was under enough load that the 1-second
timeout fired before control reached the exception block?

tapir HEAD: pilot error, insufficient SysV shmem settings

carp various: carp seems to have *serious* hardware problems, as it
has been failing randomly in all branches for a long time.  I suggest
putting that poor machine out to pasture.

penguin 8.0: fails in tsearch2.  Previous investigation says that the
failure is unfixable without initdb, which we are not going to force
for 8.0 branch.  I suggest retiring penguin from checking 8.0, as
there's not much point in continuing to see a failure there.  Or is
it worth improving buildfarm to be able to skip specific tests?

penguin 7.4: fails in initdb, with what seems to be a variant of the
alignment issue that kills tsearch2 in 8.0.  We won't fix this either,
so again might as well stop tracking this branch on this machine.

cobra, stoat, sponge 7.4: pilot error.  Either install Tk or configure
--without-tk.

firefly 7.4: dblink test fails, with what looks like an rpath problem.
Another one that we fixed awhile ago, and the fix worked on every
platform but this one.

firefly 7.3: trivial regression diffs; we could install variant
comparison files if anyone cared.

cobra, stoat, caribou 7.3: same Tk configuration error as in 7.4 branch

Firefly is obviously the outlier here.  I dunno if anyone cares enough
about SCO to spend time investigating it (I don't).  Most of the others
just need a little bit of attention from the machine owner.
        regards, tom lane