application: Check libhandy version at compilation

This only enables the dark style preference if we have
a libhandy version of 1.5.0 or newer.

src/calls-application.c

@@ -358,15 +358,19 @@ startup (GApplication *application)
 {
   g_autoptr (GtkCssProvider) provider = NULL;
   g_autoptr (GError) error = NULL;
+#if HDY_CHECK_VERSION(1, 5, 0)
   HdyStyleManager *style_manager;
+#endif
 
   G_APPLICATION_CLASS (calls_application_parent_class)->startup (application);
 
   hdy_init ();
 
+#if HDY_CHECK_VERSION(1, 5, 0)
   style_manager = hdy_style_manager_get_default ();
 
   hdy_style_manager_set_color_scheme (style_manager, HDY_COLOR_SCHEME_PREFER_LIGHT);
+#endif
 
   if (!call_audio_init (&error))
     {

src/meson.build

@@ -31,7 +31,7 @@ calls_includes = [ top_include, src_include ]
 
 calls_deps = [ dependency('gobject-2.0', version: '>= 2.58'),
                dependency('gtk+-3.0'),
-               dependency('libhandy-1', version: '>= 1.5.0'),
+               dependency('libhandy-1', version: '>= 1.4.0'),
                dependency('libfeedback-0.0'),
                dependency('libpeas-1.0'),
                dependency('gom-1.0'),