...as started to appear (with sufficiently recent Clang versions only, it
appears) after c5fcb476 "toolkit: avoid
-Werror=deprecated-copy (GCC trunk towards GCC 9)":

> [CXX] toolkit/source/controls/spinningprogress.cxx
> toolkit/source/controls/spinningprogress.cxx:38:5: error: Unreferenced externally invisible function definition [loplugin:unreffun]
>     SpinningProgressControlModel(SpinningProgressControlModel &&) = default;
>     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change-Id: Id78cd2d801e9760dde9e0a594e2b62ec20840204
Reviewed-on: https://gerrit.libreoffice.org/58180
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>