As things stand, it's pretty easy to make some changes to Gambit that cause it to segfault, and accidentally install that version so you can't build a new Gambit without bootstrapping from the git history. Would it help to add some kind of "smoke test" at the beginning of `make install` that always runs even if you omit `make check`?
Publishing recent, known-good "boot.tgz" files at a known URL could be useful too.