graph_enable_by_vertex
graph_enable_by_vertex(v, enabled, 0);
graph_enable_by_vertex(v, enabled, 1);
graph_enable_by_vertex(v, 0, 0);
graph_enable_by_vertex(v, 0, 0);
graph_enable_by_vertex(v, 0, 0);
graph_enable_by_vertex(v, 0, 0);
graph_enable_by_vertex(v, 0, 0);
void graph_enable_by_vertex(graph_vertex_t *, int, int);
graph_enable_by_vertex(v, v->gv_flags & GV_ENABLED, 0);