Make sure IOV_MAX is defined.

We stopped defining IOV_MAX on non-Windows systems in 75357ab94, on
the assumption that every non-Windows system defines it in <limits.h>
as required by X/Open.  GNU Hurd, however, doesn't follow that
standard either.  Put back the old logic to assume 16 if it's
not defined.

Author: Michael Banck <[email protected]>
Co-authored-by: Christoph Berg <[email protected]>
Reviewed-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/[email protected]
Discussion: https://postgr.es/m/[email protected]
Backpatch-through: 16

0 files changed, 0 insertions, 0 deletions