Add an xf86PrintBacktrace wrapper around xorg_backtrace to aid driver debugging.

hw/xfree86/common/xf86.h

@@ -205,6 +205,7 @@ void xf86InterceptSignals(int *signo);
 void xf86InterceptSigIll(void (*sigillhandler)(void));
 Bool xf86EnableVTSwitch(Bool new);
 void xf86ProcessActionEvent(ActionEvent action, void *arg);
+void xf86PrintBacktrace(void);
 
 /* xf86Helper.c */
 

hw/xfree86/common/xf86Events.c

@@ -632,6 +632,16 @@ xf86SigHandler(int signo)
   FatalError("Caught signal %d.  Server aborting\n", signo);
 }
 
+/*
+ * xf86PrintBacktrace --
+ *    Print a stack backtrace for debugging purposes.
+ */
+_X_EXPORT void
+xf86PrintBacktrace(void)
+{
+    xorg_backtrace();
+}
+
 #define KeyPressed(k) (keyc->postdown[k >> 3] & (1 << (k & 7)))
 #define ModifierDown(k) ((keyc->state & (k)) == (k))