This variable may be set to a path to install to when cross-compiling. This can
be useful if the path in
CMAKE_SYSROOT is read-only, or otherwise
should remain pristine.
CMAKE_STAGING_PREFIX location is also used as a search prefix
find_* commands. This can be controlled by setting the
RUNPATH entries passed to the linker contain the
CMAKE_STAGING_PREFIX, the matching path fragments are replaced