[libFuzzer] Diff 28 - [AflDriver] Update platform flags in the afl driver.

lib/Fuzzer/afl/afl_driver.cpp

 AFL_DRIVER_EXTRA_STATS_FILENAME: Setting this causes afl_driver to write extra
 statistics to the file specified. Currently these are peak_rss_mb
 (the peak amount of virtual memory used in MB) and slowest_unit_time_secs. If
 the file does not exist it is created. If the file does exist then
 afl_driver assumes it was restarted by afl-fuzz and will try to read old
 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>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #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
 // to stderr and abort(). Otherwise do nothing. Note that setting
 // AFL_DRIVER_STDERR_DUPLICATE_FILENAME may cause error_message to be appended
 // to the file as well, if the error occurs after the duplication is performed.
 #define CHECK_ERROR(cond, error_message)                                       \
   if (!(cond)) {                                                               \