[gtk/gtk-3-22: 1/2] Include C headers in introspection file.

[Christoph Reiter <creiter src gnome org>]

commit 91498c7db34481c9014dd63f235a1679fc4b8bfb
Author: Tomasz Miąsko <tomasz miasko gmail com>
Date:   Sun Mar 4 00:00:00 2018 +0000

    Include C headers in introspection file.
    
    Include gtk/gtk.h and gtk/gtk-a11y.h unconditionally,
    and gtk/gtkx.h when building with X11. Ensures that
    introspection data contains complete set required
    headers, which is useful when generating C code based
    on introspection data.
    
    Diff for generated gir (when using X11):
    
    ```diff
       <include name="xlib" version="2.0"/>
       <package name="gtk+-3.0"/>
    +  <c:include name="gtk/gtk-a11y.h"/>
    +  <c:include name="gtk/gtk.h"/>
    +  <c:include name="gtk/gtkx.h"/>
       <namespace name="Gtk"
                  version="3.0"
    ```
    
    Fixes issue #56.

 gtk/Makefile.am | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index 63f88e9476..92f6ec734f 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -1594,9 +1594,11 @@ Gtk_3_0_gir_SCANNERFLAGS =                       \
        --add-include-path=$(top_builddir)/gdk  \
        --include-uninstalled=$(top_builddir)/gdk/Gdk-3.0.gir
 Gtk_3_0_gir_INCLUDES = Atk-1.0
+Gtk_3_0_gir_C_INCLUDES = gtk/gtk.h gtk/gtk-a11y.h
 if USE_X11
 Gtk_3_0_gir_SCANNERFLAGS += --add-include-path=$(top_builddir)/gdk/x11
 Gtk_3_0_gir_INCLUDES += xlib-2.0
+Gtk_3_0_gir_C_INCLUDES += gtk/gtkx.h
 endif
 Gtk_3_0_gir_CFLAGS = \
                $(AM_CPPFLAGS) \