I started to learn Zig these days and adjusted patches for Zig a bit. Other than this, I have added a install-source? argument to zig-build-system, it can now install package source to "/src/<name>-<version>".
"-Dtarget" is used in zig-build-system's native builds as well, same as Zig for reproducibility. Made "#:zig-inputs" a private keyword, its value will be passed to inputs like cargo-build-system (the build system doesn't extract the whole closure for now, this can be added in the future depending on how Zig ecosystem develops). Set ZIG_GLOBAL_CACHE_DIR and ZIG_LOCAL_CACHE_DIR to "/tmp/zig-cache", and set ZIG_LIBC instead of using "zig build --libc", for convenience. I think this is mostly ready ( again :) ). If there's nothing else missing, I'll post the current status and call for packages to test the build system on guix-devel, together with the concern on generated files.