Fix broken symlink path

--- a/cmake/QtPostProcessHelpers.cmake
+++ b/cmake/QtPostProcessHelpers.cmake
@@ -883,7 +883,7 @@
             endif()
         endif()
         qt_path_join(tool_target_path "${CMAKE_INSTALL_PREFIX}" "${INSTALL_BINDIR}" "${filename}")
-        qt_path_join(tool_link_path "${INSTALL_PUBLICBINDIR}" "${linkname}${PROJECT_VERSION_MAJOR}")
+        qt_path_join(tool_link_path "${CMAKE_INSTALL_PREFIX}" "${INSTALL_PUBLICBINDIR}" "${linkname}${PROJECT_VERSION_MAJOR}")
         _qt_internal_relative_path(tool_target_path BASE_DIRECTORY ${tool_link_base_dir})
         list(APPEND lines "${tool_target_path} ${tool_link_path}")
     endforeach()