[vala] cairo: Mark filename parameter for PdfSurface nullable

[Michal Hruby <mhruby src gnome org>]

commit e55a3ae23fabe68c83573c7fb641c456eec68bdc
Author: Michal Hruby <michal mhr gmail com>
Date:   Thu Mar 10 22:31:55 2011 +0100

    cairo: Mark filename parameter for PdfSurface nullable
    
    Fixes bug 644158.

 vapi/cairo.vapi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/vapi/cairo.vapi b/vapi/cairo.vapi
index 0ebc50b..bc2d8cd 100644
--- a/vapi/cairo.vapi
+++ b/vapi/cairo.vapi
@@ -511,7 +511,7 @@ namespace Cairo {
 	[CCode (cname = "cairo_surface_t", cheader_filename = "cairo-pdf.h")]
 	public class PdfSurface : Surface {
 		[CCode (cname = "cairo_pdf_surface_create")]
-		public PdfSurface (string filename, double width_in_points, double height_in_points);
+		public PdfSurface (string? filename, double width_in_points, double height_in_points);
 		[CCode (cname = "cairo_pdf_surface_create_for_stream")]
 		public PdfSurface.for_stream (WriteFunc write_func, double width_in_points, double height_in_points);
 		public void set_size (double width_in_points, double height_in_points);