windows-nat: Use gdb_realpath

Use gdb_realpath instead of realpath in windows-nat.c:windows_make_so,
so that we don't have to manually call free.

Approved-By: John Baldwin <jhb@FreeBSD.org>
Change-Id: Id3cda7e177ac984c9a5f7c23f354e72bd561edff
1 file changed