Provide instructions for reproducing the output fonts from source

[Kangie]

It is unreasonable for an "Open Source" product to:

1. Check output into VCS (This is what Release Artefacts are for)
2. Not provide any guidance for users / distributions that desire to build the product themselves

Please, at the very least, update the README to include any dependencies and provide an appropriate, cross-platform, make file.

[jenskutilek]

I agree that it should be documented, but from my outside view on this project, either of these methods should work:

• Use GlyphsApp to open the source files and export from there (macOS only);
• or make a Python virtual environment and install fontmake which in turn will depend on glyphsLib and can be used to build the fonts

[justDeeevin]

As of Jan 18, 2024, after cloning with 380f29b3277ff46b8bd8577bdd7d1b60358e6c6c at the HEAD, running fontmake -g "sources/Monaspace Krypton.glyphs" -o ttf fails with this error:

fontmake: Error: In 'sources/Monaspace Krypton.glyphs' -> 'master_ufo/MonaspaceKrypton.designspace' -> 'master_ufo/MonaspaceKrypton-Light.ufo': Compiling UFO failed: monaspace/master_ufo/MonaspaceKrypton-Light.ufo/features.fea:182:1: Expected glyph class definition or statement: got NAME condition

(The actual error displays the full path to features.fea. I've removed everything leading up to monaspace)

This is error occurs for all the other fonts (using -o variable where necessary). Am I using fontmake incorrectly or is there really an error here?