[sysprof] build: ignore post-install unless gtk app is installed

[Christian Hergert <chergert src gnome org>]

commit 21fc5609f21ac35309ee268a514185c03ae09c69
Author: Christian Hergert <chergert redhat com>
Date:   Fri Feb 7 11:04:03 2020 -0800

    build: ignore post-install unless gtk app is installed

 meson.build | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index fe97c34..2d97c0a 100644
--- a/meson.build
+++ b/meson.build
@@ -190,4 +190,6 @@ subdir('examples')
 subdir('help')
 subdir('po')
 
-meson.add_install_script('build-aux/meson/post_install.sh')
+if get_option('enable_gtk')
+  meson.add_install_script('build-aux/meson/post_install.sh')
+endif