xfree86: add VT owner interface

This is just a simple interface to avoid accessing x86Screens[0]
directly.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@gmail.com>

hw/xfree86/common/xf86.h

@@ -238,6 +238,7 @@ extern _X_EXPORT void xf86InterceptSigIll(void (*sigillhandler) (void));
 extern _X_EXPORT Bool xf86EnableVTSwitch(Bool new);
 extern _X_EXPORT void xf86ProcessActionEvent(ActionEvent action, void *arg);
 extern _X_EXPORT void xf86PrintBacktrace(void);
+extern _X_EXPORT Bool xf86VTOwner(void);
 
 /* xf86Helper.c */
 

hw/xfree86/common/xf86Events.c

@@ -768,3 +768,12 @@ DDXRingBell(int volume, int pitch, int duration)
 {
     xf86OSRingBell(volume, pitch, duration);
 }
+
+Bool
+xf86VTOwner(void)
+{
+    /* at system startup xf86Screens[0] won't be set - but we will own the VT */
+    if (xf86NumScreens == 0)
+	return TRUE;
+    return xf86Screens[0]->vtSema;
+}