exists, otherwise we install it anyway. I interpret this as a very
high desire to install ${PROG}.help. Alas, ${PROG}.help doesn't exist
at the moment and neither does loader.help, so in practice this just
doesn't work, no matter how you interpret it. The compromise is to
install ${PROG}.help IFF it exists. I realize we lost creativity with
this commit, but style should have been preserved, AFAICT :-)