GIMP vs. rsvg-convert for building PSPP

[Ben Pfaff]

PSPP currently uses GIMP to generate PNGs from SVGs. GIMP is
heavyweight, slow, and commonly not installed on developer systems, so
we run it from Smake as pre-configuration.

There's a newer program called rsvg-convert that is much more commonly
available these days. It is lightweight, fast, and more commonly
installed (it is a binary that comes with the rsvg library, which is
itself widely used). It produces good-quality output. I think that we
could switch to it from GIMP, run it at build time instead of as part
of Smake, and thereby improve the build process.

Does anyone have comments on this?