Unfunny_Umi we removed it because you don't need to compile anymore + that compiler is old and filled with issues, what's the point?
The only thing you need to install and write scripts is this doc
https://plutonium.pw/docs/modding/loading-mods/#t6
If for a good reason you need a compiler then use gsc-tool
https://plutonium.pw/docs/modding/gsc/compiler-limitations/