[cmake-developers] Add command line options for deprecation message control

[Stephen Kelly]

Michael Scott wrote:

> Thanks for the comments, here is the previous patch, with the suggested
> amendments.

Thanks for working on this.

I'm wondering how these new command line options relate to the existing 
options -Wdev and -Wno-dev. Is there any reason not to make those existing 
options set the CMAKE_WARN_DEPRECATED variable? 

What is the difference between the intended uses of those existing options 
and the intended uses of the new options, given that -Wno-dev is mostly 
useful for third parties to silence policy warnings? 

If the new options are merged to master should -Wdev and -Wno-dev also be 
changed to affect CMAKE_WARN_DEPRECATED?

Thanks,

Steve.