Should font-build-system compile sfd fonts?

[Brendan Tildesley]

I'm calling for anyone's opinion on this. Currently there are a few
fonts which more-or-less copy-paste the same code for compiling sfd
files in to ttf and otf, which requires fontforge. I wish to add another
font, but didn't want to add to this duplication. Most fonts don't
require it, but it wouldn't be harmful, apart from dragging in
fontforge, would adding a 'build phase that does this to
font-build-system be reasonable. I'm not actually sure how to add a
required native-input to a build system. Or is there a better idea?
Making a whole new sfd-font-build-system, or defining a build-sdf-fonts
symbol that could be added with modify-phases and adding fontforge to
native-inputs?