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

dlls/dhcpcsvc/Makefile.in

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

dlls/dhcpcsvc/dhcpcsvc.c

@@ -30,21 +30,6 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(dhcpcsvc);
 
-BOOL WINAPI DllMain( HINSTANCE hinst, DWORD reason, LPVOID reserved )
-{
-    TRACE("%p, %u, %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;
-}
-
 void WINAPI DhcpCApiCleanup(void)
 {
     FIXME(": stub\n");