long is 32 bit on Windows x86_64 platform

So that this is always wrong (on this platform) to write:

reinterpret_cast<foo>(reinterpret_cast<long>(bar))

it should be:
renterpret_cast<foo>(reinterpret_cast<sal_uIntPtr>(bar))

Change-Id: Ia286246ee1616988f755c2d2054b26efacc51af0
Reviewed-on: https://gerrit.libreoffice.org/13366
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>