message: fix xcode 12 build
diff: @@ -362,7 +362,7 @@ void DomTree::buildDominators() {
  }
  // build predecessors relationship
  - for (const auto &[src, tgt, instr] : cfg) {
  + for (auto [src, tgt, instr] : cfg) {
  (void)instr;
  doms.at(&tgt).preds.push_back(&doms.at(&src));
  }
  