the former was a bit error-prone and eg. since 2b9ed6c7 (2023-05-15),
icon.icns was not copied (just to old bundle but not re-copied to GUI
bundle). Also things like Vulcan shaderes were not copied.
Here, we use a no-clobber option not to override files specific to GUI
bundle.
+ fixed the actaull path of icon.icns inside the bundle