diff --git a/reactos/lib/user32/misc/dllmain.c b/reactos/lib/user32/misc/dllmain.c
index bbfaa2e1c07..1cad93609f6 100644
--- a/reactos/lib/user32/misc/dllmain.c
+++ b/reactos/lib/user32/misc/dllmain.c
@@ -1,4 +1,3 @@
-#undef __USE_W32API
 #include <windows.h>
 #include <debug.h>
 #include <ddk/ntddk.h>
@@ -12,6 +11,9 @@
 #include <strpool.h>
 #include <roscfg.h>
 
+/* FIXME: Belongs to some header. */
+WINBOOL STDCALL GdiDllInitialize(HANDLE, DWORD, LPVOID);
+
 #ifdef DBG
 
 /* See debug.h for debug/trace constants */