message: Make CompilerOptions flags private again
diff: @@ -30,15 +30,15 @@ pub struct StoreOptions {
  pub struct CompilerOptions {
  /// Use Singlepass compiler.
  #[clap(long, conflicts_with_all = &["cranelift", "llvm"])]
  - pub singlepass: bool,
  + singlepass: bool,
  /// Use Cranelift compiler.
  #[clap(long, conflicts_with_all = &["singlepass", "llvm"])]
  - pub cranelift: bool,
  + cranelift: bool,
  /// Use LLVM compiler.
  #[clap(long, conflicts_with_all = &["singlepass", "cranelift"])]
  - pub llvm: bool,
  + llvm: bool,
  /// Enable compiler internal verification.
  #[clap(long)]
  