but maybe we don't actually need to merge the gftools patch? If we can pip install from a git rev or branch, we could just maintain our own branch of gftools and not need to dirty up the main tree.
we skip noto fonts and other fonts that have a custom recipe provider
there are a number of failures because it turns out that in lots of cases one source does produce multiple fonts; a bunch of these I could address by turning off config options (so to not build small caps or italics) but a handful of fonts are building a regular and a bold, and I didn't see a config option for this.
This wires everything up to get gftools working in crater.