Fix a number of mingw warnings

Fix a number of mingw warnings

Move to definition inside the ifdef where they are used to avoid
unused warnings.

Fix a few printf related warnings when DWORD is used as paramter and
the printf format should be %lu (long unsigned int)

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210421134348.1950392-4-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22176.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>