Added missing DriverCallBack function.
diff --git a/relay32/winmm.spec b/relay32/winmm.spec
index c6d167b..8ba51f8 100644
--- a/relay32/winmm.spec
+++ b/relay32/winmm.spec
@@ -7,7 +7,7 @@
3 stub WINMM_3
4 stdcall CloseDriver(long long long) CloseDriver
5 stdcall DefDriverProc(long long long long long) DefDriverProc
- 6 stub DriverCallback
+ 6 stdcall DriverCallback(long long long long long long long) DriverCallback
7 stdcall DrvClose(long long long) CloseDriver
8 stdcall DrvDefDriverProc(long long long long long) DefDriverProc
9 stdcall DrvGetModuleHandle(long) GetDriverModuleHandle