Disable fcntl directory notify constants on Mono

Author: BCSharp

src/core/IronPython.Modules/fcntl.cs

@@ -537,6 +537,8 @@ private static bool TryGetInt64(object? obj, out long value) {
 
     // Linux only
     #region Generated Directory Notify Flags
+#if NET
+    // Disabled on Mono because of inability to open directory descriptors
 
     // *** BEGIN GENERATED CODE ***
     // generated by function: generate_DN_flags from: generate_os_codes.py
@@ -572,5 +574,6 @@ private static bool TryGetInt64(object? obj, out long value) {
 
     // *** END GENERATED CODE ***
 
+#endif
     #endregion
 }