vcl: convert a couple of macros to static functions

Change-Id: I037dd97049aecff023f0ffb8dfdbb772dbde7ae0
Reviewed-on: https://gerrit.libreoffice.org/11069
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>