[gnome-software] Fix build when gtkspell enabled

[Kalev Lember <klember src gnome org>]

commit 51e317ceafdb0fcf586d7d728843cde55a7b9414
Author: Balló György <ballogyor gmail com>
Date:   Thu Jan 18 19:41:32 2018 +0100

    Fix build when gtkspell enabled
    
    HAVE_GTKSPELL needs to be defined, otherwise gtkspell using code doesn't
    get built.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=792658

 meson.build     |    1 +
 src/meson.build |    4 ++++
 2 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/meson.build b/meson.build
index 00f3b2a..c20f8a6 100644
--- a/meson.build
+++ b/meson.build
@@ -125,6 +125,7 @@ endif
 
 if get_option('enable-gtkspell')
   gtkspell = dependency('gtkspell3-3.0')
+  conf.set('HAVE_GTKSPELL', 1)
 endif
 
 if get_option('enable-polkit')
diff --git a/src/meson.build b/src/meson.build
index bf18924..c90366b 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -100,6 +100,10 @@ if get_option('enable-gnome-desktop')
   gnome_software_dependencies += [gnome_desktop]
 endif
 
+if get_option('enable-gtkspell')
+  gnome_software_dependencies += [gtkspell]
+endif
+
 executable(
   'gnome-software',
   resources_src,