g.gui: 'gui' parameter not required

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32781 15284696-431f-4ddb-bdfa-cd5b030d7da7

general/g.gui/main.c

@@ -40,7 +40,6 @@ int main(int argc, char *argv[])
     type = G_define_option();
     type->key = "gui";
     type->type = TYPE_STRING;
-    type->required = YES;
     type->label = _("GUI type");
     type->description = _("Default value: GRASS_GUI if defined otherwise wxpython");
     type->descriptions = _("tcltk;Tcl/Tk based GUI - GIS Manager (gis.m);"