[CMake] Executable extension (MSVC)

[John Drescher]

>  I know for a fact that this is not correct. I have written my own
>  single windows applications that have a gui and a console and it is a
>  .exe. Link the gui application with subsystem console.
>
Ok. I found what I do. I have a post build step (in a vc6 project
.dsp) that changes the subsystem to console after the build.

PostBuild_Cmds=editbin /SUBSYSTEM:CONSOLE $(TARGETPath)

John