libc changes and freebsd-4 compatible binaries

[justin at shiningsilence.com]

> The two basic options are:
> (1) Provide a port / package analog to misc/compat4x (misc/compatdf12 ?).
> For the mean time, it could be automatically installed with the LiveCD.
> (2) Push them as binaries into src/lib/compat or so and install them
> with the normal world.

If we do (1), what happens to folks using pkgsrc?  Right now, the system
still works if you remove all ports.