Revert "make clipboard patch obsolete"

This reverts commit 77c51c5a6b16387f1792e23acbcf2080f790aa25.

Having multiple clipboards are useful, for example for plumber scripts.
I've discussed this on IRC and it is useful to have.

x.c

@@ -507,7 +507,6 @@ xsetsel(char *str, Time t)
 	XSetSelectionOwner(xw.dpy, XA_PRIMARY, xw.win, t);
 	if (XGetSelectionOwner(xw.dpy, XA_PRIMARY) != xw.win)
 		selclear_(NULL);
-	xclipcopy();
 }
 
 void