ibus: room for a thousand input contexts

Toolkits keep one IBus context per widget that ever took focus, so 64
across every client could run out in a long session, after which new
widgets silently got no input method. The table is static and small
(about 100 bytes a slot).

ibus.c

@@ -15,7 +15,8 @@ enum
 {
 	Maxconns	= Maxclients,
 	Maxwatches	= 2*Maxconns + 1,
-	Maxcontexts	= Maxclients,
+	/* Toolkits keep one context per widget that ever took focus. */
+	Maxcontexts	= 1024,
 	Relmask		= 1<<30,
 	Ownerpoll	= 200,	/* ms between owner checks while a preedit shows */
 	/* IBus wire constants; the daemon does not link libibus. */