sfc_os: Use --prefer-native instead of DLL_WINE_PREATTACH.

dlls/sfc_os/Makefile.in

 MODULE    = sfc_os.dll
 IMPORTLIB = sfc_os
 
-EXTRADLLFLAGS = -mno-cygwin
+EXTRADLLFLAGS = -mno-cygwin -Wb,--prefer-native
 
 C_SRCS = sfc_os.c

dlls/sfc_os/sfc_os.c

@@ -31,25 +31,6 @@
 WINE_DEFAULT_DEBUG_CHANNEL(sfc);
 
 /******************************************************************
- *      DllMain
- */
-BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
-{
-    TRACE("(%p, %d, %p)\n",hinstDLL, fdwReason, lpvReserved);
-
-    switch(fdwReason)
-    {
-        case DLL_WINE_PREATTACH:
-            return FALSE;           /* prefer native version */
-
-        case DLL_PROCESS_ATTACH:
-            DisableThreadLibraryCalls( hinstDLL );
-            break;
-    }
-    return TRUE;
-}
-
-/******************************************************************
  *      SfcGetNextProtectedFile     [sfc_os.@]
  */
 BOOL WINAPI SfcGetNextProtectedFile(HANDLE handle, PROTECTED_FILE_DATA *data)