The macOS beta release notes under the 3rd party apps known issues section, mention that CMake might not work correctly, and the solution is to update 3.18rc1.
Does anyone know what the issue is, and which commit in 3.18rc1 fixed it?
Link: https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11-beta-release-notes
We don’t know. No one from Apple has reached out to us about this. Those release notes are the first we’ve learned of any issues for CMake.
For reference, support for macOS Big Sur is tracked by CMake Issue 20863.
After the output of what @gjasny found when testing master, my suspicion is that this MR fixed it. It added .tbd as a shared library suffix and those files still exist individually in the SDK.
We should investigate whether backporting this MR to 3.17 allows us to make a 3.17 patch release which works (since it is an env-regression and is likely doable earlier than 3.18.0 final as well).
find_library on macOS has been able to find .tbd files since CMake 3.4 (commit 67f60958b6).