libxl: fix build with Xen4.3

Xen 4.3 fixes a mistake in the libxl event handler signature where the
event owned by the application was defined as const.  Detect this and
define the libvirt libxl event handler signature appropriately.
(cherry picked from commit 43b0ff5b1eb7fbcdc348b2a53088a7db939d5e48)

diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index ff8d8be2fe96baad1928c9a89bc2537de4e348be..adaec7557975cf7b6a071f1bff2c1f55297746f0 100644 (file)
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -696,10 +696,22 @@ libxlVmReap(libxlDriverPrivatePtr driver,
 }
 
 /*
- * Handle previously registered event notification from libxenlight
+ * Handle previously registered event notification from libxenlight.
+ *
+ * Note: Xen 4.3 removed the const from the event handler signature.
+ * Detect which signature to use based on
+ * LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG.
  */
+
+#ifdef LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG
+# define VIR_LIBXL_EVENT_CONST /* empty */
+#else
+# define VIR_LIBXL_EVENT_CONST const
+#endif
+
 static void
-libxlEventHandler(void *data ATTRIBUTE_UNUSED, const libxl_event *event)
+libxlEventHandler(void *data ATTRIBUTE_UNUSED,
+                  VIR_LIBXL_EVENT_CONST libxl_event *event)
 {
     libxlDriverPrivatePtr driver = libxl_driver;
     virDomainObjPtr vm = NULL;