Introduce new variable for Table 40 - Internet socket options

[jwakely]

Instead of repeating "if F == AF_INET6" several times, we could introduce a new variable:

and let F be the value of p.family()and let v6 be the value of p.family() == AF_INET6.

Then just use "if v6" in the table.

[jwakely]

Here's what the result looks like