diff --git a/libc/stdio/fopen.c b/libc/stdio/fopen.c
index a6cddd3..6d2d882 100644
--- a/libc/stdio/fopen.c
+++ b/libc/stdio/fopen.c
@@ -31,6 +31,8 @@
  * SUCH DAMAGE.
  */
 
+#define __USE_BSD
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>