Wow. After some gentle nudging recently from Jarkko and Nick Ing-Simmons, I finally got around to trying to build MacPerl with PerlIO instead of SFIO. And sure enough, it worked. Amazing. Nick did remarkable work. PerlIO handles almost all of the IO perl needs. I just needed to redefine Sfio_t and FILE as PerlIO, and add dTHX to a few spots, and everything -- except for system() outputting to STDOUT -- is Just Working. All of the core test suite is passing as it should.
Sure, the system() problem needs to be fixed, but it will be. One bug -- so far; I suppose more could pop up -- in building with a new IO system on a completely untested platform is just impressive. And this particular problem is not in PerlIO anyway, but an expected roadblock we figured we'd need to address. Once more, great job, Nick.