+#ifndef __FreeBSD__
+# ifndef MAP_STACK
+# define MAP_STACK 0
+# endif
+#else /* FreeBSD MAP_STACK always return -ENOMEM */
+# define MAP_STACK 0
+#endif
+
+#ifndef MAP_GROWSDOWN
+#define MAP_GROWSDOWN 0
+#endif
+
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON