Make wmaker XRandR aware

This patch makes wmaker automatically Restart() to take into account
resolution changes done by xrandr.

The motivation to write this patch is that when I start my laptop connected
to an external monitor (VGA1), the resolution in the monitor is initially
wrong (perhaps this is a bug in XOrg or OpenSuse, but anyway), so I always
do this after starting wmaker:

xrandr --output VGA1 --preferred

The resolution in the external monitor gets fixed, but wmaker does not
recognize the change automatically and I have to manually restart it.

So this patch avoids the last step by making wmaker be XRandR-aware.
Wmaker now restarts automatically when it receives a RRChangeScreenNotify
event and I don't have to do the last part of the silly procedure described
above.

I am not sure if restarting wmaker is the most elegant solution, but
it at least solves part of my issue with wmaker + xrandr.

src/event.c

@@ -40,6 +40,10 @@
 #include "xdnd.h"
 #endif
 
+#ifdef HAVE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
+
 #ifdef KEEP_XKB_LOCK_STATUS
 #include <X11/XKBlib.h>
 #endif				/* KEEP_XKB_LOCK_STATUS */
@@ -96,6 +100,11 @@ extern int wShapeEventBase;
 extern int wXkbEventBase;
 #endif
 
+#ifdef HAVE_XRANDR
+extern Bool has_randr;
+extern int randr_event_base;
+#endif
+
 /* special flags */
 /*extern char WDelayedActionSet;*/
 
@@ -562,6 +571,10 @@ static void handleExtensions(XEvent * event)
 		handleXkbIndicatorStateNotify(event);
 	}
 #endif				/*KEEP_XKB_LOCK_STATUS */
+#ifdef HAVE_XRANDR
+	if (has_randr && event->type == (randr_event_base + RRScreenChangeNotify))
+		Restart(NULL,True);
+#endif
 }
 
 static void handleMapRequest(XEvent * ev)