WIP: cmExecuteProcess: Proof of concept for ASYNC processes
This is not production code quality and should not be reviewed as one. It is used only to discuss ASYNC processes possibilities.
For use cases please see test files
This brings ASYNC START/AWAIT to execute_process Similar idea was proposed in #18929 for try_compile, but apparently execute_process is simpler case of try_compile, so it can be practised here
Edited by Artur Ryt