...which required some lax placements of SAL_WARN_UNUSED_RESULT to be fixed.
Also, Clang unfortunately is rather picky about the relative order of
SAL_WARN_UNUSED_RESULT expanding to [[nodiscard]] and uses of the DLLPUBLIC
macros (expanding to __attribute__(...) resp. __declspec(..) for clang-cl).

Change-Id: Iae6ca36bef97f1864873aefdb5f05c7f5e045ad3
Reviewed-on: https://gerrit.libreoffice.org/60274
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>