message: fix another LLVM deprecation
diff: @@ -127,7 +127,7 @@ class llvm2alive_ : public llvm::InstVisitor<llvm2alive_, unique_ptr<Instr>> {
  template <typename T>
  uint64_t pref_alignment(T &i, llvm::Type *ty) const {
  auto a = i.getAlign().value();
  - return a != 0 ? a : DL().getPrefTypeAlignment(ty);
  + return a != 0 ? a : DL().getPrefTypeAlign(ty).value();
  }
  Value* convert_constexpr(llvm::ConstantExpr *cexpr) {
  