[CMake] Forwarding parameters to cmake through cmake-gui

[John Drescher]

> +1 for updating cmake-gui to work equally to ccmake
>
> But my opinion regarding CMAKE_MODULE_PATH is different. The problem is that
> alot of the default find-modules don't work because the dependency is not in
> the location where the find-module expects it. Currently there are only two
> workarounds:
> - Change the find-module directly so it works in the local environment
> - Change the CMakeLists.txt of the project - which is bad because it's just
> a LOCAL problem and the CMakeLists should be mostly independent of the
> environment.
>
> With the command-line option it's possible to setup a custom cmake-gui batch
> file once per computer which sets e.g. the CMAKE_MODULE_PATH to a directory
> with customized find modules. If one doesn't want to use custom find modules
> that's fine too but I think everyone should have the option to place
> dependent libraries wherever she/he wants.
>

For these kind of things I use environment variables in my
CMakeLists.txt. If the environment variable is set I use it. If not I
use the default behavior.

John