> I build.sh'ed for the first time since oct-14, and the build aborts
> after installing the new ld.elf_so...
...
> /usr/libexec/ld.elf_so -> /libexec/ld.elf_so
> Illegal instruction - core dumped

This is actually a kernel bug.  One page is not being synced correctly
in the I$ on some systems.