[CMake] RPATH cross-compile issue with CHECK_*_EXISTS

[Brad King]

On 02/27/2017 03:50 PM, Jörg Krause wrote:
> The problem is...

Thanks.  I've opened an issue for this here:

 https://gitlab.kitware.com/cmake/cmake/issues/16682

>> These are set on by default in `Modules/Platform/UnixPaths.cmake` but
>> disabled on Debian by `Modules/Platform/Linux.cmake` except when
>> cross compiling.  If a toolchain file specifies CMAKE_SYSTEM_NAME
>> such that a custom `Platform/MySystem.cmake` file is loaded then
>> the latter can set them as needed for the target platform.
> 
> Thanks for the hint. We are discussing this setting as a workaround.

It sounds like this target platform does not want the lib32/lib64
suffixes to be searched so this would be an appropriate setting
for the projects to use regardless of what is done about this in
upstream CMake.  That will also fix it for using CMake 3.7.

-Brad