[gdk-pixbuf] meson: Install the marshalers header

[Emmanuele Bassi <ebassi src gnome org>]

commit e9b4c41b130998b3c9a3f34b8f64122cc91c6718
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Apr 25 16:34:51 2018 +0100

    meson: Install the marshalers header
    
    The generated marshalers are public API, and the header needs to be
    installed, even though nobody should be using them.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=795213

 gdk-pixbuf/meson.build |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gdk-pixbuf/meson.build b/gdk-pixbuf/meson.build
index 58d54f7..66946b9 100644
--- a/gdk-pixbuf/meson.build
+++ b/gdk-pixbuf/meson.build
@@ -84,7 +84,9 @@ gdkpixbuf_sources = [
 
 gdkpixbuf_marshals = gnome.genmarshal('gdk-pixbuf-marshal',
                                       sources: 'gdk-pixbuf-marshal.list',
-                                      prefix: '_gdk_pixbuf_marshal')
+                                      prefix: '_gdk_pixbuf_marshal',
+                                      install_header: true,
+                                      install_dir: join_paths(gdk_pixbuf_includedir, gdk_pixbuf_api_path))
 
 gdkpixbuf_enums = gnome.mkenums('gdk-pixbuf-enum-types',
                                 sources: gdkpixbuf_headers,