remove bad assertion, added new ones in clear_pixmap()
diff --git a/src/mesa/drivers/x11/xm_dd.c b/src/mesa/drivers/x11/xm_dd.c
index f9eb877..5b3c89c 100644
--- a/src/mesa/drivers/x11/xm_dd.c
+++ b/src/mesa/drivers/x11/xm_dd.c
@@ -307,8 +307,12 @@
const XMesaContext xmesa = XMESA_CONTEXT(ctx);
XMesaBuffer xmbuf = XMESA_BUFFER(ctx->DrawBuffer);
- assert(xrb->pixmap == xmbuf->backxrb->pixmap ||
- xrb->pixmap == xmbuf->frontxrb->pixmap);
+ assert(xmbuf);
+ assert(xrb->pixmap);
+ assert(xmesa);
+ assert(xmesa->display);
+ assert(xrb->pixmap);
+ assert(xmbuf->cleargc);
if (all) {
XMesaFillRectangle( xmesa->display, xrb->pixmap, xmbuf->cleargc,