Adding riodraw patch

patches.def.h

@@ -769,6 +769,13 @@
  */
 #define RESTARTSIG_PATCH 0
 
+/* Adds rio-like drawing to resize the selected client.
+ * This depends on an external tool slop being installed.
+ * This patch was backported from instantWM.
+ * https://github.com/bakkeby/patches/blob/master/dwm/dwm-riodraw-6.2.diff
+ */
+#define RIODRAW_PATCH 0
+
 /* This patch let's you rotate through the stack using keyboard shortcuts.
  * https://dwm.suckless.org/patches/rotatestack/
  */