How can I build my programs for different architectures?

PVM doesn't do it automatically, but the procedure can often be automated easily - if your directories are cross-mounted and you use aimk (§4.1.1).

A script such as the following builds a program for each of several machines in parallel, tagging the make output with the host name:

    foreach m (ig thud cranberry garlic)
        rsh $m "cd $cwd ; make" < /dev/null \
        |& sed -e "s/^/${m}: /" &
    end