[vte] vala: Fix build with vala 0.43+ git master due to empty struct definition

[Rico Tzschichholz <ricotz src gnome org>]

commit 53690d5cee51bdb7c3f7680d3c22b316b1086f2c
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Dec 1 19:04:59 2018 +0100

    vala: Fix build with vala 0.43+ git master due to empty struct definition
    
    This should get a proper refactoring as the FIXME suggests.
    
    See https://gitlab.gnome.org/GNOME/vte/issues/76

 bindings/vala/app.vala | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/bindings/vala/app.vala b/bindings/vala/app.vala
index 8663d63c..a534e76b 100644
--- a/bindings/vala/app.vala
+++ b/bindings/vala/app.vala
@@ -819,6 +819,8 @@ class App : Gtk.Application
 
   public struct Options
   {
+    //FIXME Merge this struct into App class
+    public int dummy;
     public static bool audible = false;
     public static string? command = null;
     private static string? cjk_ambiguous_width_string = null;