[libFuzzer] more refactoring

llvm-svn: 282113
diff --git a/llvm/lib/Fuzzer/FuzzerDefs.h b/llvm/lib/Fuzzer/FuzzerDefs.h
index fa8ef57..b871771 100644
--- a/llvm/lib/Fuzzer/FuzzerDefs.h
+++ b/llvm/lib/Fuzzer/FuzzerDefs.h
@@ -14,6 +14,7 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
+#include <cstring>
 #include <string>
 #include <vector>