socket_wrapper: inject O_LARGEFILE to open[64|at]() if needed

On 32bit systems this is normally done by glibc if _FILE_OFFSET_BITS is 64,
but with socket wrapper we don't want to define _FILE_OFFSET_BITS=64,
as we need to overload open64 explicitly. But we need to inject
O_LARGEFILE for being transparent to the application.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15251

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>