cmake 3.24 empty automoc code triggers lots of warnings

With clang it triggers

'cmake_automoc_silence_linker_warning' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit [-Werror,-Wweak-vtables]

With clazy it triggers

Polymorphic class cmake_automoc_silence_linker_warning is copyable. Potential slicing. [-Wclazy-copyable-polymorphic]

Makes it really hard for projects that aim for no warnings in their code base that the cmake generated code triggers that many