Hello dehesa,

To provide support for arm64 architecture on macOS for our client library, we depend on the same support from J2ObjC. At the moment it is not yet available, but I'm sure they are working on it.

As a temporary workaround, you can exclude the arm64 architecture from the build settings of your macOS target. Follow these steps:
- Go to Build Settings.
- Open Architectures (the first group).
- Open the Excluded Architectures subgroup.
- Add a line for Debug.
- Select "Any SDK" and enter "arm64" as the setting value.
- Add a line for Release.
- Select "Any SDK" and enter "arm64" as the setting value.

This should fix the build errors, but of course it will also exclude support for ARM processors from your target. It will still run on ARM Macs through Rosetta, though.

As soon as J2ObjC provides support for the arm64 architecture, we will add it to our client library.