Added `SystemConfiguration.framework` to the Xcode project to fix
undefined symbols errors building without the interpreter, like:
`_SCNetworkReachabilityScheduleWithRunLoop`.
Added explicit static constructors to the generated `NativeCalls`
class to avoid a `TypeInitializationException` at startup when
Godot attempts to read the static fields (like `godot_api_hash`)
from this class.
This seems to be an issue with Mono's AOT compiler and classes
with the `beforefieldinit` attribute. Not sure if it only happens
when the fields are only accessed via reflection as was our case.
Explicitly declaring the static constructor makes the C# compiler
not add the `beforefieldinit` attribute to the class.
4838e609ee