MacOS 15. XCode 12.
Issue and Reproduction Steps
This issue bugged me a lot for the last 2 days and there didn't seem to be any open/closed previous issues regarding this.
#21482 briefly mentioned this issue, but its an older release and the solutions listed did not help me at all.
Answer/Solution: You go to your respective project folder -> node_modules -> react-native call-keep -> iOS -> open the workspace file.
Go to the build settings and under the "Library Header Files"... add the following and save it: