message: Tolerate missing gtk-update-icon-cache
diff: @@ -52,4 +52,4 @@ dist_uiicons_DATA = \
  window-close.png
  install-data-hook:
  - gtk-update-icon-cache -f -t $(DESTDIR)$(iconsdir)
  + which gtk-update-icon-cache >/dev/null && gtk-update-icon-cache -f -t $(DESTDIR)$(iconsdir) || true
  