diff --git a/include/libc/libc_fcntl.h b/include/libc/libc_fcntl.h
index 83b9af9b1e..1b7c69b1f4 100644
--- a/include/libc/libc_fcntl.h
+++ b/include/libc/libc_fcntl.h
@@ -20,7 +20,7 @@
 #include <fcntl.h>
 
 #ifndef O_NONBLOCK
-#define O_NONBLOCK   04000
+#define O_NONBLOCK   0x4000
 #endif
 
 #if defined(_WIN32)
@@ -35,7 +35,7 @@
 #endif
 
 #ifndef O_DIRECTORY
-#define O_DIRECTORY 0200000
+#define O_DIRECTORY 0x200000
 #endif
 
 #ifndef O_BINARY