Today I upgraded to xcode 12.2 (on Catalina), and Juce 6.0.4 (from Juce 5.4.7).
After upgrading I successfully compiled both a debug and a release build of one of my plugins. In my initial test the release build worked fine - it passes all tests in pluginval and works in Reaper.
However the debug build is not recognised by Reaper or other DAWs I’ve tested in. When I scan for new plugins it is not found.
EDIT: I should have mentioned that I use xcodebuild to build my plugin from the command line without ever opening Xcode. If I perform a debug build from the actual Xcode app then Reaper recognises the plugin. So I guess something about the way I’m using xcodebuild no longer works the same way. I’ll keep digging, but in case anyone can spot the problem, here is my xcodebuild command:
xcodebuild -project /path/to/my.xcodeproj -alltargets -configuration Debug SYMROOT=~/Library/Developer/Xcode/DerivedData