Fix 64 bit install

CMakeLists.txt

   endif()
 endif()
 
+get_property(LIB64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
+
+if ("${LIB64}" STREQUAL "TRUE")
+  set(LIBSUFFIX 64)
+else()
+  set(LIBSUFFIX "")
+endif()
+
 install( TARGETS ${EXECUTABLE_NAME} DESTINATION "${CMAKE_INSTALL_PREFIX}/bin" )
-install( TARGETS ${LIBRARY_NAME} DESTINATION "${CMAKE_INSTALL_PREFIX}/lib" )
+install( TARGETS ${LIBRARY_NAME} DESTINATION "${CMAKE_INSTALL_PREFIX}/lib${LIBSUFFIX}" )
 install( FILES ${CMAKE_SOURCE_DIR}/src/slop.hpp DESTINATION "${CMAKE_INSTALL_PREFIX}/include" COMPONENT development )
 install( FILES "${CMAKE_SOURCE_DIR}/${MANTARGET}" DESTINATION  "${CMAKE_INSTALL_MANDIR}/man1" COMPONENT doc )