+
+#if defined(__APPLE__)
+# include <AvailabilityMacros.h>
+# ifndef MAC_OS_X_VERSION_10_12
+# define MAC_OS_X_VERSION_10_12 101200
+# endif
+# define HAVE_WORKING_MMAP (MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12)
+#elif defined(__FreeBSD__)
+# define HAVE_WORKING_MMAP 0
+#else
+# define HAVE_WORKING_MMAP 1
+#endif