commit eb2fa4068fcdf6e4aaeb4e98e26d444e3e739bde
Author: Christian Holler <choller@mozilla.com>
Date:   Thu Jul 30 18:20:54 2020 +0200

    [libFuzzer] Allow external functions to be defined at runtime

diff --git a/FuzzerDriver.cpp b/FuzzerDriver.cpp
index 5928d1d96acd..ff43cb031dff 100644
--- a/FuzzerDriver.cpp
+++ b/FuzzerDriver.cpp
@@ -653,7 +653,8 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
   using namespace fuzzer;
   assert(argc && argv && "Argument pointers cannot be nullptr");
   std::string Argv0((*argv)[0]);
-  EF = new ExternalFunctions();
+  if (!EF)
+    EF = new ExternalFunctions();
   if (EF->LLVMFuzzerInitialize)
     EF->LLVMFuzzerInitialize(argc, argv);
   if (EF->__msan_scoped_disable_interceptor_checks)