IF(CPACK_GENERATOR STREQUAL "TGZ" OR CPACK_GENERATOR STREQUAL "TBZ2")
    set(CPACK_PACKAGING_INSTALL_PREFIX "")
ELSEIF (CPACK_GENERATOR STREQUAL "RPM" )
    set(CPACK_PACKAGING_INSTALL_PREFIX ${CPACK_INSTALL_PREFIX})
ELSEIF (CPACK_GENERATOR STREQUAL "STGZ")
    set(CPACK_PACKAGING_INSTALL_PREFIX "")
ENDIF()