[CMake] Help with cmake_policy

[Emmanuel Blot]

> Manu, are you actually cutting release snapshots for the customer and
> delivering them outside your version control trunk?  In that case you
> can make -Wno-dev the default by adding

We deliver SDKs, however CMake binaries are not bundled along with our  
SDKs.

A SDK that builds w/o a single warning message in our premises may  
throw "unexpected" warning messages when a client builds it with a  
newer CMake version (patch-release). I'd really like to avoid this  
kind of trouble.

It would be ok to get a single line about missing policy, but the  
current warning messages do look scary.

>  if(NOT DEFINED CMAKE_SUPPRESS_DEVELOPER_WARNINGS)
>    set(CMAKE_SUPPRESS_DEVELOPER_WARNINGS 1 CACHE INTERNAL "No dev  
> warnings")
>  endif()

Yeah, this could be an option.

I agree with Alexander though: it would be nice to get a less scary  
warning message when a new policy is yet to be defined.

BTW, it would be nice to get a *single* warning message about the  
experimental status of assembly language support:
for now, if a project contains N subprojects (library, executable)  
using ASM, CMake throws N identical warning messages.

Thanks for your help,
Manu