This reverts commit 8ec2cb5544b86306b702484ea785b6b9596562ab.
We don't have any code anywhere in libcurl (or the curl tool) that use
wcsdup so there's no such memory use to track. It seems to cause mild
problems with the Borland compiler though that we may avoid by reverting
this change again.
Bug: http://curl.haxx.se/mail/lib-2013-05/0070.html