Compiling the rust 1.91.1 port on FreeBSD amd64 13.5-R p6 resulted in multiple SIGSEGV errors. After tracking down a Bugzilla thread (I would link but now can't find it) the advice seemed to be to keep typing make after each error. Lo and behold, this worked! I was wary that the resulting rust compiler would be less than operable, but, no, it worked fine.