diff --git a/extern/pfd-fixed/portable-file-dialogs.h b/extern/pfd-fixed/portable-file-dialogs.h
index 3d90a854f..fc6df0a14 100644
--- a/extern/pfd-fixed/portable-file-dialogs.h
+++ b/extern/pfd-fixed/portable-file-dialogs.h
@@ -1331,6 +1331,14 @@ inline std::string internal::file_dialog::select_folder_vista(IFileDialog *ifd,
 
 // notify implementation
 
+#if _WIN32
+inline BOOL WINAPI icon_enum_callback(HMODULE hModule, LPCTSTR lpType, LPTSTR lpName, LONG_PTR lParam)
+{
+    ((NOTIFYICONDATAW *)lParam)->hIcon = ::LoadIcon(GetModuleHandle(nullptr), lpName);
+    return false;
+};
+#endif
+
 inline notify::notify(std::string const &title,
                       std::string const &message,
                       icon _icon /* = icon::info */)
@@ -1383,14 +1391,8 @@ inline notify::notify(std::string const &title,
         /* case icon::info: */ default: nid->dwInfoFlags = NIIF_INFO; break;
     }
 
-    ENUMRESNAMEPROC icon_enum_callback = [](HMODULE, LPCTSTR, LPTSTR lpName, LONG_PTR lParam) WINAPI -> BOOL
-    {
-        ((NOTIFYICONDATAW *)lParam)->hIcon = ::LoadIcon(GetModuleHandle(nullptr), lpName);
-        return false;
-    };
-
     nid->hIcon = ::LoadIcon(nullptr, IDI_APPLICATION);
-    ::EnumResourceNames(nullptr, RT_GROUP_ICON, icon_enum_callback, (LONG_PTR)nid.get());
+    ::EnumResourceNames(nullptr, RT_GROUP_ICON, (ENUMRESNAMEPROC)icon_enum_callback, (LONG_PTR)nid.get());
 
     nid->uTimeout = 5000;