installs something. This is not 100% right, since it has a false hit
when install -C snaps hard links.
Also, run strip(1) from the $PATH, otherwise you need a special version
of install to install (say) elf binaries which have a different strip.
With JDP's elfkit, the layout of the path determines which binary format
you are generating.
allow the user to install using a Numeric GID or UID.
this brings it in to line with chgrp and chown, ans is required
by some people using FreeBSD in a product.
time of the target if the target file is the same as the source),
-d (debug), and -p (same as -C except for preserving the modification
time of the source if the target doesn't exists or is different from
the source.
Use library err() functions instead of our own and pass them better
exit codes.
Submitted by: wollman (and changed a lot by me)
