message: fix type signature for malloc and free calls
diff: @@ -865,7 +865,7 @@ llvm::FunctionType* Compiler::BlockType(const stripe::Block& block) {
  llvm::Function* Compiler::MallocFunction(void) {
  std::vector<llvm::Type*> argtypes{IndexType()};
  - llvm::Type* rettype = builder_.getInt8PtrTy()->getPointerTo();
  + llvm::Type* rettype = builder_.getInt8PtrTy();
  auto functype = llvm::FunctionType::get(rettype, argtypes, false);
  auto linkage = llvm::Function::ExternalLinkage;
  const char* funcname = "malloc";
  @@ -873,7 +873,7 @@ llvm::Function* Compiler::MallocFunction(void) {
  }
  llvm::Function* Compiler::FreeFunction(void) {
  - llvm::Type* ptrtype = builder_.getInt8PtrTy()->getPointerTo();
  + llvm::Type* ptrtype = builder_.getInt8PtrTy();
  std::vector<llvm::Type*> argtypes{ptrtype};
  llvm::Type* rettype = llvm::Type::getVoidTy(context_);
  auto functype = llvm::FunctionType::get(rettype, argtypes, false);
  