Add American Fuzzy Lop (afl) to third_party/afl/

third_party/afl/src/test-instr.c

+/*
+   american fuzzy lop - a trivial program to test the build
+   --------------------------------------------------------
+
+   Written and maintained by Michal Zalewski <lcamtuf@google.com>
+
+   Copyright 2014 Google Inc. All rights reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at:
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int main(int argc, char** argv) {
+
+  char buf[8];
+
+  if (read(0, buf, 8) < 1) {
+    printf("Hum?\n");
+    exit(1);
+  }
+
+  if (buf[0] == '0')
+    printf("Looks like a zero to me!\n");
+  else
+    printf("A non-zero value? How quaint!\n");
+
+  exit(0);
+
+}