[gtk: 1/2] Allow GTK4 to be added as a subproject

[Matthias Clasen <matthiasc src gnome org>]

commit 72700d16440ef8663a9e8d73a7debd270fde9950
Author: BogDan Vatra <bogdan kde org>
Date:   Fri Feb 26 09:27:02 2021 +0200

    Allow GTK4 to be added as a subproject

 meson.build | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index f3dba9d276..145a848a86 100644
--- a/meson.build
+++ b/meson.build
@@ -810,7 +810,9 @@ else
   message('Not executing post-install steps automatically when cross compiling')
 endif
 
-meson.add_dist_script('build-aux/meson/dist-theme.py')
+if not meson.is_subproject()
+    meson.add_dist_script('build-aux/meson/dist-theme.py')
+endif
 
 if host_machine.system() != 'windows'
   # Install Valgrind suppression files (except on Windows,