remove DitherValues

src/mesa/drivers/x11/xm_api.c

@@ -794,8 +794,6 @@ noFaultXAllocColor( int client,
 static GLboolean setup_grayscale( int client, XMesaVisual v,
                                   XMesaBuffer buffer, XMesaColormap cmap )
 {
-   (void) DitherValues;		/* Muffle compiler */
-
    if (GET_VISUAL_DEPTH(v)<4 || GET_VISUAL_DEPTH(v)>16) {
       return GL_FALSE;
    }