This reverts commit b9d7957b.

Amin Bandali authored 2 years ago and Adrien Béraud committed 2 years ago

Up until now, these were only set by the GNU Build System in
configure.ac, and so the pkg-config files generated from CMake builds
did not have the right Libs.private and Requires.private, especially
useful when linking statically.

- VOIP notifications for iOS < 14.5
- alert and background notifications for iOS >= 14.5

Fix typo in 2.4.1 release

Reason for partial revert:
Adding the atomic library is meant by CheckAtomic
to be automatic through CMAKE_REQUIRED_LIBRARIES.