fuzz: make standalone_fuzz_target_runner call LLVMFuzzerInitialize

Otherwise some of our fuzzers crash when they try and use Python.

Differential Revision: https://phab.mercurial-scm.org/D7565

contrib/fuzz/standalone_fuzz_target_runner.cc

@@ -1,41 +1,45 b''
 // Copyright 2017 Google Inc. All Rights Reserved.
 // Licensed under the Apache License, Version 2.0 (the "License");
 
 // Example of a standalone runner for "fuzz targets".
 // It reads all files passed as parameters and feeds their contents
 // one by one into the fuzz target (LLVMFuzzerTestOneInput).
 // This runner does not do any fuzzing, but allows us to run the fuzz target
 // on the test corpus (e.g. "do_stuff_test_data") or on a single file,
 // e.g. the one that comes from a bug report.
 
 #include <cassert>
 #include <fstream>
 #include <iostream>
 #include <vector>
 
 // Forward declare the "fuzz target" interface.
 // We deliberately keep this inteface simple and header-free.
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
 
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv);
+
 int main(int argc, char **argv)
 {
+	LLVMFuzzerInitialize(&argc, &argv);
+
 	for (int i = 1; i < argc; i++) {
 		std::ifstream in(argv[i]);
 		in.seekg(0, in.end);
 		size_t length = in.tellg();
 		in.seekg(0, in.beg);
 		std::cout << "Reading " << length << " bytes from " << argv[i]
 		          << std::endl;
 		// Allocate exactly length bytes so that we reliably catch
 		// buffer overflows.
 		std::vector<char> bytes(length);
 		in.read(bytes.data(), bytes.size());
 		assert(in);
 		LLVMFuzzerTestOneInput(
 		    reinterpret_cast<const uint8_t *>(bytes.data()),
 		    bytes.size());
 		std::cout << "Execution successful" << std::endl;
 	}
 	return 0;
 }
 // no-check-code since this is from a third party