Add basic structure for fuzzing targets

General changes:

* Add -D/--deterministic command line option as
  convenience/alternative to -G/--load-seeds (i.e. no file needed, it just
  uses zero-initialized random seeds).  It also changes Broker data
  stores over to using deterministic timing rather than real time.

* Add option to make Reporter abort on runtime scripting errors

src/fuzzers/FuzzBuffer.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <cstddef>
+
+namespace zeek {
+
+struct FuzzBuffer {
+
+	static constexpr int PKT_MAGIC_LEN = 4;
+	static constexpr unsigned char PKT_MAGIC[PKT_MAGIC_LEN + 1] = "\1PKT";
+
+	FuzzBuffer(const unsigned char* data, size_t size)
+		: begin(data), end(data + size)
+		{ }
+
+	bool Valid() const;
+
+	int Next(const unsigned char** chunk, size_t* len, bool* is_orig);
+
+	const unsigned char* begin;
+	const unsigned char* end;
+};
+
+} // namespace zeek