setsockopt return value is not checked

[WesleyRosenblum]

Problem:

The return value of setsockopt is not checked in several places in s2n_socket.c, for example: https://github.com/aws/s2n-tls/blob/main/utils/s2n_socket.c#L123

Some of the uses of setsockopt have the comment /* Ignore the return value, if it fails it fails */, but others do not, so its not clear if it was intentional.

Solution:

Either check the return value, or add a comment

• Does this change what S2N sends over the wire? No
• Does this change any public APIs? No

Requirements / Acceptance Criteria:

Uses of setsockopt either check the return value or have a comment explaining why it is not checked