user32: Add a stub implementation of RegisterServicesProcess.

dlls/user32/user32.spec

@@ -563,7 +563,7 @@
 # @ stub RegisterMessagePumpHook
 @ stub RegisterNetworkCapabilities
 @ stdcall RegisterRawInputDevices(ptr long long)
-@ stub RegisterServicesProcess
+@ stdcall RegisterServicesProcess(long)
 @ stdcall RegisterShellHookWindow (long)
 @ stdcall RegisterSystemThread(long long)
 @ stdcall RegisterTasklist (long)

dlls/user32/user_main.c

@@ -331,3 +331,12 @@ BOOL WINAPI ExitWindowsEx( UINT flags, DWORD reason )
     CloseHandle( pi.hThread );
     return TRUE;
 }
+
+/***********************************************************************
+ *		RegisterServicesProcess (USER32.@)
+ */
+int WINAPI RegisterServicesProcess(DWORD ServicesProcessId)
+{
+    FIXME("(0x%x): stub\n", ServicesProcessId);
+    return 0;
+}