Revert "gmmproc: Pass 0 (NULL) instead of  to C functions."
Revert "gmmproc: Pass 0 (NULL) instead of  to C functions."

This reverts commit 5acce15576a91aec89c04b8fe5f8532b192acb71.

GNOME/glibmm,johne53/MB3Glibmm,GNOME/glibmm,johne53/MB3Glibmm,johne53/MB3Glibmm,GNOME/glibmm,johne53/MB3Glibmm,GNOME/glibmm,GNOME/glibmm