message: reduce suggested backends to the ones compiled into wasmer
diff: @@ -105,7 +105,22 @@ enum Backend {
  impl Backend {
  pub fn variants() -> &'static [&'static str] {
  - &["singlepass", "cranelift", "llvm"]
  + #[cfg(all(feature = "backend:singlepass", feature = "backend:llvm"))]
  + {
  + &["cranelift", "singlepass", "llvm"]
  + }
  + #[cfg(all(not(feature = "backend:singlepass"), feature = "backend:llvm"))]
  + {
  + &["cranelift", "llvm"]
  + }
  + #[cfg(all(feature = "backend:singlepass", not(feature = "backend:llvm")))]
  + {
  + &["cranelift", "singlepass"]
  + }
  + #[cfg(all(not(feature = "backend:singlepass"), not(feature = "backend:llvm")))]
  + {
  + &["cranelift"]
  + }
  }
  }
  