[balsa/gtk4: 130/314] build: Depend on gtk4

[Peter Bloomfield <peterb src gnome org>]

commit 0138019193e3fac920eeca6bfb74030eafe6c52b
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Mon Sep 21 15:50:12 2020 -0400

    build: Depend on gtk4

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index fd8ecf7d6..35ef6c0be 100644
--- a/meson.build
+++ b/meson.build
@@ -129,7 +129,7 @@ conf.set('TOOLKIT_CATEGORIES', TOOLKIT_CATEGORIES)
 
 # Dependencies for balsa and balsa_ab:
 glib_dep    = dependency('glib-2.0',  version : '>= 2.48.0')
-gtk_dep     = dependency('gtk+-3.0',  version : '>= 3.24.0')
+gtk_dep     = dependency('gtk4'                            )
 gmime_dep   = dependency('gmime-3.0', version : '>= 3.2.6' )
 gio_dep     = dependency('gio-2.0'                         )
 gthread_dep = dependency('gthread-2.0'                     )