which was taken from OpenBSD/pica.
The previous revision of elf.c replaced Ted Lemon's elf exec machinery
with something closer to Christos' MI elf machinery. It turns out
that old NetBSD/pmax elf binaries have three segments, and the newer
elf exec machinery cannot exec them.
The old elf exec machinery is folded back into cpu_exec.c, which falls
back onto using the old machinery if the new machinery fails. The
old-style binaries will be deprecated at the 1.2 release.