remove dependency on badrect

Reference: /n/atom/patch/applied/nobadrect
Date: Tue Apr 15 20:47:55 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libmemdraw/draw.c	Tue Apr 15 20:47:55 2014
+++ /sys/src/libmemdraw/draw.c	Tue Apr 15 20:47:55 2014
@@ -221,7 +221,7 @@
 	int splitcoords;
 	Rectangle omr;
 
-	if(badrect(*r))
+	if(r->min.x>=r->max.x || r->min.y>=r->max.y)
 		return 0;
 	splitcoords = (p0->x!=p1->x) || (p0->y!=p1->y);
 	/* clip to destination */