Mark managed callback functions if they're only used in the dynamic registrar,
and only initialize the corresponding delegate if the dynamic registrar is
available.
This will make it possible for the linker to remove those managed functions if
the dynamic registrar is being removed.
You were the preprocessor we wished C# had natively
Removing PMCS requires these changes:
* Remove XamCore from src/
* Remove XamCore from tools/
* Remove XamCore from runtime/
* nint/nuint enum conversion
* _compat_ enum conversion
* NSAction conversion
* Hand fix single API incorrectly converted by PMCS to unbreak compatibility
- Due to a bug in PMCS, the nuint was incorrectly converted in this API.
- However, as that ship as sailed, we must "fix" it until XAMCORE_4_0
* Update readme
* Bump macios-binaries
Rolf Bjarne Kvinge
Chris Hamons