[gtk] Fix the build

[Matthias Clasen <matthiasc src gnome org>]

commit dd4bb00a24fc4f848350dbc0dd27ce660019b5b6
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Feb 15 18:22:53 2018 -0500

    Fix the build
    
    This was a mis-merge.

 modules/input/meson.build | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/modules/input/meson.build b/modules/input/meson.build
index eb026f4705..ac13c8c193 100644
--- a/modules/input/meson.build
+++ b/modules/input/meson.build
@@ -37,6 +37,14 @@ endforeach
 immodules_subdir = 'gtk-4.0/@0@/immodules'.format(gtk_binary_version)
 immodules_install_dir = join_paths(gtk_libdir, immodules_subdir)
 
+# Format:
+#  - protocol name
+#  - protocol stability ('stable' or 'unstable')
+#  - protocol version (if stability is 'unstable')
+proto_sources = [
+  ['gtk-text-input', 'stable', ],
+]
+
 im_wayland_gen_headers = []
 im_wayland_sources = files('imwayland.c')
 wayland_scanner = find_program('wayland-scanner')