Out of the hundred or so times I've tried to build snapshots, nearly every
failure has had to do with a difference between flist and DESTDIR.  (Except
for x86 boot floppies being 4k too large.)

In general, I never actually care about this.  It's fine by me that there's
a couple of extra postfix files; I'm running -current, I *expect* a few
quirks.

Is there a trivial way to specify that these differences should be reported
and politely ignored, letting the build complete?

-s