Achievements: Fix building Qt frontend with achievements disabled

src/frontend-common/CMakeLists.txt

@@ -1,6 +1,4 @@
 add_library(frontend-common
-  achievements.cpp
-  achievements.h
   common_host.cpp
   common_host.h
   fullscreen_ui.cpp

src/frontend-common/fullscreen_ui.cpp

@@ -11,6 +11,7 @@
 #include "common/string_util.h"
 #include "common/threading.h"
 #include "common_host.h"
+#include "core/achievements.h"
 #include "core/bios.h"
 #include "core/cheats.h"
 #include "core/controller.h"

src/frontend-common/imgui_overlays.cpp

@@ -1,6 +1,5 @@
 #include "imgui_overlays.h"
 #include "IconsFontAwesome5.h"
-#include "achievements.h"
 #include "common/assert.h"
 #include "common/file_system.h"
 #include "common/log.h"