Add interval timer to XIM updates

Signed-off-by: Joseph Benden <joe@benden.us>

config.h

@@ -51,6 +51,13 @@ static unsigned int actionfps = 30;
  */
 static unsigned int blinktimeout = 800;
 
+/*
+ * interval (in milliseconds) between each successive call to ximspot. This
+ * improves terminal performance while not reducing functionality to those
+ * whom need XIM support.
+ */
+int ximspot_update_interval = 1000;
+
 /*
  * thickness of underline and bar cursors
  */
@@ -184,6 +191,7 @@ ResourcePref resources[] = {
 		{ "cwscale",      FLOAT,   &cwscale },
 		{ "chscale",      FLOAT,   &chscale },
 		{ "alpha",        FLOAT,   &alpha },
+		{ "ximspot_update_interval", INTEGER, &ximspot_update_interval },
 };
 
 /*