Turn off validateReferences for the iOS Resolver

[a-maurice]

By default, DLLs imported into Unity will validate all their references at load time. The iOS Resolver depends on the Unity iOS Support Library being present, which is not true by default for Windows developers. By turning off validateReferences, the library will no longer throw an exception at load time, but instead at runtime, which the library itself can handle instead.

#412
#622

[StephenHodgson]

This did not fix the problem.

Tried with Unity 6000.0.49f1 with only Android and Windows IL2CPP modules installed.

Assembly 'Packages/com.google.firebase.app/Firebase/Editor/Firebase.Editor.dll' will not be loaded due to errors:
Unable to resolve reference 'UnityEditor.iOS.Extensions.Xcode'. Is the assembly missing or incompatible with the current platform?
Reference validation can be disabled in the Plugin Inspector.

[a-maurice]

@StephenHodgson Odd. In your project, is "Validate References" still enabled for the Google.IOSResolver.dll? This change should make it off by default, but that error message seems like it is still on for you.

[StephenHodgson]

@a-maurice having to change properties inside of client projects is not a valid solution to this problem.

[a-maurice]

@StephenHodgson I'll admit, I'm confused here. My change is for the metadata of the DLL, which is in a versioned folder, so even on an update it should be replacing it, and getting the new metadata for it. The solution you had with using Define Constraints would similarly be an metadata file change, but had the issue of removing the 'iOS Resolver' settings from the Asset toolbar, which some developers do need because of cloud builds.

There is a larger fix, which would be to completely remove any direct dependency on the Unity iOS logic by using reflection, and I do have that seemingly working here, but I wanted more time to test it since it is a much more dangerous change: https://github.com/googlesamples/unity-jar-resolver/tree/am-xcode_dependency

But based on local testing, it seemed like setting validateReferences to off would cover most cases. I was even able to remove the iOS installation on our nightly test runners because of it, so I'm confused on why it doesn't seem to work for you.