[vala-extra-vapis] cairo-xcb: fix XcbSurface constructor visual argument

[Evan Nemerson <evann src gnome org>]

commit eca036a94f5526137c93bf8453132952f850d0c4
Author: Evan Nemerson <evan nemerson com>
Date:   Sun Nov 2 22:14:42 2014 -0800

    cairo-xcb: fix XcbSurface constructor visual argument
    
    https://github.com/nemequ/vala-extra-vapis/issues/13

 cairo-xcb.vapi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/cairo-xcb.vapi b/cairo-xcb.vapi
index 066ac9f..ff4a8a8 100644
--- a/cairo-xcb.vapi
+++ b/cairo-xcb.vapi
@@ -25,7 +25,7 @@ namespace Cairo {
        [CCode (cname = "cairo_surface_t", cheader_filename = "cairo-xcb.h")]
        public class XcbSurface : Surface {
                [CCode (cname = "cairo_xcb_surface_create")]
-               public XcbSurface (Xcb.Connection connection, Xcb.Drawable drawable, Xcb.VisualType visual, 
int width, int height);
+               public XcbSurface (Xcb.Connection connection, Xcb.Drawable drawable, Xcb.VisualType? visual, 
int width, int height);
                public void set_size (int width, int height);
        }
 }