#ifdef __linux__
-#elif __FreeBSD__
+#elif defined(__FreeBSD__)
#define MAP_GROWSDOWN 0
#define MAP_ANONYMOUS MAP_ANON
#else
-#error "Please add support for your OS into compat/mman.h."
+#error "Please add support for your OS."
#endif /* __linux__ , __FreeBSD__ */
#endif /* _COMPAT_MMAN_H */