user32: Add stub implementations of MessageBoxTimeoutA/W.

dlls/user32/msgbox.c

@@ -454,6 +454,26 @@ INT WINAPI MessageBoxExW( HWND hWnd, LPCWSTR text, LPCWSTR title,
 }
 
 /**************************************************************************
+ *      MessageBoxTimeoutA (USER32.@)
+ */
+INT WINAPI MessageBoxTimeoutA( HWND hWnd, LPCSTR text, LPCSTR title,
+                               UINT type, WORD langid, DWORD timeout )
+{
+    FIXME("timeout not supported (%u)\n", timeout);
+    return MessageBoxExA( hWnd, text, title, type, langid );
+}
+
+/**************************************************************************
+ *      MessageBoxTimeoutW (USER32.@)
+ */
+INT WINAPI MessageBoxTimeoutW( HWND hWnd, LPCWSTR text, LPCWSTR title,
+                               UINT type, WORD langid, DWORD timeout )
+{
+    FIXME("timeout not supported (%u)\n", timeout);
+    return MessageBoxExW( hWnd, text, title, type, langid );
+}
+
+/**************************************************************************
  *		MessageBoxIndirectA (USER32.@)
  */
 INT WINAPI MessageBoxIndirectA( LPMSGBOXPARAMSA msgbox )

dlls/user32/user32.spec

@@ -498,8 +498,8 @@
 @ stdcall MessageBoxExW(long wstr wstr long long)
 @ stdcall MessageBoxIndirectA(ptr)
 @ stdcall MessageBoxIndirectW(ptr)
-# @ stub MessageBoxTimeoutA
-# @ stub MessageBoxTimeoutW
+@ stdcall MessageBoxTimeoutA(long str str long long long)
+@ stdcall MessageBoxTimeoutW(long wstr wstr long long long)
 @ stdcall MessageBoxW(long wstr wstr long)
 # @ stub ModifyAccess
 @ stdcall ModifyMenuA(long long long long ptr)