- Move computation of extended build-tree rpath
    to cmComputeLinkInformation
  - Only enable the extended build-tree rpath if
    the target will be installed
  - Generalize the interface of file(CHRPATH)
  - When changing the rpath on installation only
    replace the part generated by CMake because
    the native tools (ex SunCC on Linux) might have
    added their own part to the rpath