Fix initialization of Rectilinear filler

lib/Slic3r/Layer/Region.pm

@@ -269,7 +269,10 @@ sub make_perimeters {
         
         # fill gaps
         if ($Slic3r::Config->gap_fill_speed > 0 && $Slic3r::Config->fill_density > 0 && @gaps) {
-            my $filler = Slic3r::Fill::Rectilinear->new(layer_id => $self->layer->id);
+            my $filler = Slic3r::Fill::Rectilinear->new(
+                bounding_box    => [ $self->layer->object->print->bounding_box ],
+                layer_id        => $self->layer->id,
+            );
             
             # we should probably use this code to handle thin walls and remove that logic from
             # make_surfaces(), but we need to enable dynamic extrusion width before as we can't