Allow enum values to be used as a const for staticarray initialisation

[woollybah]

Since enum values are essentially consts, the following should work :

SuperStrict

Framework brl.standardio

Enum MyEnum
    first
    count
End Enum

Struct MyStruct
    Field StaticArray enumerated:Int[MyEnum.count]
End Struct

but fails because of the error : Static array initialiser must be constant