[CMake] new rpath support

[Zachary Pincus]

Hi folks,

A quick question about the support for adding custom rpaths (and on  
darwin, install_names) to shared libraries that Brad is adding to CMake:

Is there a windows equivalent to rpaths at all? Will dlls created  
with these options also be loadable at that rpath? Or is it the case  
taht on Windows there is no support for loading dll's from anywhere  
but the executable's directory, or locations on PATH?

Thanks,

Zach