Index: lib/Fuzzer/afl/afl_driver.cpp
===================================================================
--- lib/Fuzzer/afl/afl_driver.cpp
+++ lib/Fuzzer/afl/afl_driver.cpp
@@ -49,6 +49,25 @@
 statistics from the file. If that fails then the process will quit.
 
 */
+// Platform detection. Copied from FuzzerInternal.h
+#ifdef __linux__
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_LINUX 1
+#define LIBFUZZER_WINDOWS 0
+#elif __APPLE__
+#define LIBFUZZER_APPLE 1
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_WINDOWS 0
+#elif _WIN32
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_WINDOWS 1
+#else
+#error "Support for your platform has not been implemented"
+#endif
+
+#define LIBFUZZER_POSIX LIBFUZZER_APPLE || LIBFUZZER_LINUX
+
 #include <assert.h>
 #include <chrono>
 #include <iostream>
@@ -60,16 +79,6 @@
 #include <errno.h>
 #include <signal.h>
 #include <sys/resource.h>
-// Platform detection. Copied from FuzzerInternal.h
-#ifdef __linux__
-#define LIBFUZZER_LINUX 1
-#define LIBFUZZER_APPLE 0
-#elif __APPLE__
-#define LIBFUZZER_LINUX 0
-#define LIBFUZZER_APPLE 1
-#else
-#error "Support for your platform has not been implemented"
-#endif
 
 // Used to avoid repeating error checking boilerplate. If cond is false, a
 // fatal error has occured in the program. In this event print error_message