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

dlls/mprapi/Makefile.in

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

dlls/mprapi/mprapi.c

@@ -25,25 +25,6 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(mprapi);
 
-/*****************************************************
- *      DllMain
- */
-BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
-{
-    TRACE("(%p, %d, %p)\n", hinst, reason, reserved);
-
-    switch(reason)
-    {
-    case DLL_WINE_PREATTACH:
-        return FALSE;  /* prefer native version */
-
-    case DLL_PROCESS_ATTACH:
-        DisableThreadLibraryCalls( hinst );
-        break;
-    }
-    return TRUE;
-}
-
 /***********************************************************************
  * MprAdminGetErrorString (MPRAPI.@)
  *