add null implementation for non-gio notifier

CMakeLists.txt

@@ -68,6 +68,8 @@ endif ()
 
 if (NOT WIN32)
     target_sources(abaddon PRIVATE src/notifications/notifier_gio.cpp)
+else ()
+    target_sources(abaddon PRIVATE src/notifications/notifier_null.cpp)
 endif ()
 
 if (IXWebSocket_LIBRARIES)

src/notifications/notifier_null.cpp

@@ -0,0 +1,5 @@
+#include "notifier.hpp"
+
+Notifier::Notifier() {}
+
+void Notifier::Notify(const Glib::ustring &title, const Glib::ustring &text, const Glib::ustring &default_action) {}