Fix the extruder override logic. All role-based extruder options now default to 0, meaning no override is defined and the default (inherited) extruder is used. The default extruder option does not use the shortcut logic anymore (it was thus moved to be a CLI-specific logic)

lib/Slic3r/Config.pm

@@ -57,6 +57,8 @@ sub new_from_cli {
     foreach my $opt_key (keys %args) {
         if ($opt_key =~ /^(?:print_center|bed_size|duplicate_grid|extruder_offset|retract_layer_change|wipe)$/) {
             $self->set_deserialize($opt_key, $args{$opt_key});
+        } elsif (my $shortcut = $Options->{$opt_key}{shortcut}) {
+            $self->set($_, $args{$opt_key}) for @$shortcut;
         } else {
             $self->set($opt_key, $args{$opt_key});
         }