u8 literals incompatibly change their type (as implemented by recent Clang
trunk)

Change-Id: Ia4f7b91f5d86656a056303d2754981ab2093a739
Reviewed-on: https://gerrit.libreoffice.org/63494
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>