Add IPv4 socket option constant IP_PKTINFO as socket module attribute.

[dsentinel]

Feature or enhancement

Add IPv4 socket option constant IP_PKTINFO as socket module attribute.

Pitch

The socket option IP_PKTINFO is defined on Linux and OSX.
I would think we would want all the socket option constants defined in systems headers specifically <in.h> available as socket module level attributes. The most common ones are already included.

There are many other constants I would be willing to add, if desired.
In fact I'm curious if all constants should be pulled from headers dynamically.

Linked PRs

• GH-100813: Add IPv4 socket option constant IP_PKTINFO as socket module attribute #10294