[gtk+] Fix docs build

[Matthias Clasen <matthiasc src gnome org>]

commit 366fb44d2070096546623574915369fe8d93cc43
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 9 21:58:50 2017 -0400

    Fix docs build
    
    this include file can't be found, so just do without it.

 docs/reference/gtk/gtk4.types.in |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/docs/reference/gtk/gtk4.types.in b/docs/reference/gtk/gtk4.types.in
index 21e73e9..5b496db 100644
--- a/docs/reference/gtk/gtk4.types.in
+++ b/docs/reference/gtk/gtk4.types.in
@@ -1,5 +1,3 @@
-#include <gtk/gtkunixprint.h>
-
 gtk_about_dialog_get_type
 gtk_accel_group_get_type
 gtk_accel_label_get_type