rustbuild: Refactor adding steps manually
rustbuild: Refactor adding steps manually

Use a macro so it automatically picks up new steps.

GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,GBGamer/rust,graydon/rust