diff --git a/gtk/gtkwin32.c b/gtk/gtkwin32.c
index 91e9bfba96..c316824f5c 100644
--- a/gtk/gtkwin32.c
+++ b/gtk/gtkwin32.c
@@ -42,6 +42,11 @@
 static HMODULE   gtk_dll;
 extern HINSTANCE _gdk_dll_hinstance;
 
+BOOL WINAPI
+DllMain (HINSTANCE hinstDLL,
+         DWORD     fdwReason,
+         LPVOID    lpvReserved);
+
 BOOL WINAPI
 DllMain (HINSTANCE hinstDLL,
          DWORD     fdwReason,