It seems to be that we can throw away all the invisible fonts needed
for SLiTeX by generating virtual fonts of the right name which simply
leave the right amount of space. So to generate an invisible font
corresponding to foo.tfm, i need merely generate foo.pl, extract the
right information into a foo.vpl and then give myself a foo.vf.
Question: has anyone done a program already to take foo.pl and write
foo.vpl? It won't be difficult, but I don't want to waste my time if
it already exists