xcb: as we require version 1.3, let's at least test in configure for it too.

Signed-off-by: JP Dinger <jpd@videolan.org>
	(If at all possible, we should reduce the requirements instead.)

configure.ac

@@ -4064,7 +4064,7 @@ AS_IF([test "${enable_xcb}" != "no"], [
   PKG_CHECK_MODULES(XPROTO, [xproto])
 
   dnl libxcb
-  PKG_CHECK_MODULES(XCB, [xcb])
+  PKG_CHECK_MODULES(XCB, [xcb >= 1.3])
   PKG_CHECK_MODULES(XCB_SHM, [xcb-shm])
   VLC_ADD_PLUGIN([xcb])
   VLC_ADD_PLUGIN([xcb_screen])