Fix fuzzer-flags.test on Windows

The optional external function callbacks have to be exported in order
for them to be called. The test was failing because libFuzzer wasn't
calling LLVMFuzzerInitialize.

We can reconsider if this is the best way to mark these optional
callbacks exported later.

git-svn-id: svn://svn.chromium.org/llvm-project/llvm/trunk/lib/Fuzzer@308548 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
2 files changed