It seems like the master branch, and two other recent commits from when 0.13 became current don't work (with different compile errors orginating from inside the .cache folder
zig fetch --save git+https://github.com/batiati/mustache-zig
zig fetch --save git+https://github.com/batiati/mustache-zig#ae5ecc1522da983dc39bb0d8b27f5d1b1d7956e3
zig fetch --save git+https://github.com/batiati/mustache-zig#4913f1ff3b5400da604258e9c40825c91d139889