...follow-up to 4e41227d "mingw64: change Link
class to use sal_IntPtr instead of long;" should make obsolete
<https://gerrit.libreoffice.org/#/c/13659/> "Signed/Unsigned mismatch on x86_64
platform on windows"

Change-Id: I9fcc947bb96e104816c2820cb338fc34c528bae0