Add ringtone support using GSound

src/meson.build

@@ -28,6 +28,7 @@ calls_deps = [ dependency('gobject-2.0'),
                dependency('libhandy-0.0'),
                dependency('ModemManager'),
                dependency('mm-glib'),
+               dependency('gsound'),
              ]
 
 calls_sources = files(['calls-message-source.c', 'calls-message-source.h',
@@ -54,6 +55,7 @@ calls_sources = files(['calls-message-source.c', 'calls-message-source.h',
                        'calls-new-call-box.c', 'calls-new-call-box.h',
                        'calls-new-call-header-bar.c', 'calls-new-call-header-bar.h',
                        'calls-main-window.c', 'calls-main-window.h',
+                       'calls-ringer.c', 'calls-ringer.h',
                        'calls-application.c', 'calls-application.h',
                        'util.c', 'util.h',
                       ])