Make it possible to build the crate normally and on the stable toolchain while skipping over the #[ligen] macro calls when being built without cargo ligen
This is not necessary in the Ligen crate, we can allow ligen to be called but ignore it in the generators if the rustc flag is not set, which is being set in cargo-ligen before running build
Make it possible to build the crate normally and on the stable toolchain while skipping over the #[ligen] macro calls when being built without cargo ligen