rem: rotation = s->stack[rotation_idx] * M_PI / 180.0;
add: rotation = -s->stack[rotation_idx] * M_PI / 180.0;
context: gerbv_draw_prim5(GdkPixmap *pixmap, GdkGC *gc, stack_t *s, int scale,		 gint x, gint y){    const int nuf_vertices_idx = 1;    const int diameter_idx = 4;    const int rotation_idx = 5;    int nuf_vertices, i;    double vertex, tick, rotation, radius;    GdkPoint *points;    if (s->sp != 6)	return;    nuf_vertices = (int)s->stack[nuf_vertices_idx];    points = (GdkPoint *)malloc(sizeof(GdkPoint) * nuf_vertices);    if (!points) {	free(points);	return;    }    tick = 2 * M_PI / (double)nuf_vertices;    rotation = s->stack[rotation_idx] * M_PI / 180.0;    radius = s->stack[diameter_idx] / 2.0;    for (i = 0; i < nuf_vertices; i++) {	vertex =  tick * (double)i + rotation;	points[i].x = (int)round(scale * radius * cos(vertex)) + x;	points[i].y = (int)round(scale * radius * sin(vertex)) + y;    }    gdk_draw_polygon(pixmap, gc, 1, points, nuf_vertices);    free(points);    return;} /* gerbv_draw_prim5 */