APIs that use AEKeyword are less that delightful

Having to use something like this:

```csharp
public static int FourCC (string s)
{
return (((int)s [0]) << 24 |
((int)s [1]) << 16 |
((int)s [2]) << 8 |
((int)s [3]));
}
```

to pack a pseudo-enum is 😞

https://forums.xamarin.com/discussion/9774/custom-url-schema-handling

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Ref: https://bugzilla.xamarin.com/44/44572/bug.html