...after 7ffdd830
"HAVE_CPP_ATTRIBUTE_FALLTHROUGH is always true now"

Change-Id: I54e5ff4e036a6bb3e5774d1c0524158aae18e937
Reviewed-on: https://gerrit.libreoffice.org/64800
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>