buffer: Change limits for array_mult_safe

buffer: Change limits for array_mult_safe

- Lower the limit to 1GB on 32bit systems.
  The limit of 4GB-1 makes no sense on systems that usually
  don't allow a single process to allocate anything near to
  this limit.
- Increate the limit from 4GB-1 to 4GB on other systems. It
  makes no difference in protection but makes it much easier
  to use the limit in other contexts, e.g. if dividing it.

Change-Id: I4f95edd7ce2098180aa620a231727217f333a12d
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1436
Message-Id: <20251212100920.7671-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg35044.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>