Don't require cmake and ninja when the LLVM backend is not used
Don't require cmake and ninja when the LLVM backend is not used

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