Gas planet textures generated using gaseous-giganticus from Space Nerds in Space (reddit thread)
gaseous-giganticus.linux64 (the file in the root of this repository) is a compiled version for 64-bit Linux. You need libpng and zlib.
gaseous-giganticus.macos64 is compiled for 64-bit macOS. It was compiled on 10.11 (el capitan) and clang seems to have marked it as only compatible with 10.10+. I don't know if it will work on previous versions. It doesn't require libpng as it contains a statically linked version.
Still not sure about Windows version. File an issue if you really need it. For now the Linux version should work under WSL.
src contains the source code that was compiled to create the binary.