Fix test suite on FreeBSD 11

[wezm]

This PR addresses failures in the test suite on FreeBSD amd64 11.1-RELEASE-p6:

• Exclude NET_MAXID from tests as it was removed from FreeBSD.
• Update the definition of blksize_t to match its FreeBSD definition.
• Update various rlimit constants to match their FreeBSD definition.
• Update various locale constants to match their FreeBSD definitions.

With these changes all test pass.

[rust-highfive]

r? @alexcrichton

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[wezm]

So CI failed due to it running FreeBSD 10 and not having some of the constants I added (RLIMIT_KQUEUES, RLIMIT_UMTXP). This appears to be an issue in #799 (comment) as well. I can look into generating an updated qemu image if that's the right way to go about it.

[alexcrichton]

Thanks! Looks like CI may be failing though?

[wezm]

@alexcrichton yep see previous comment. Let me know the best way to proceed.

[alexcrichton]

Ah sorry was a bit too tired! I'd be fine either recreating the image yeah! If you need help with that I think the old steps are documented in the readme in the ci dir, but I can try to help out otherwise.

If that fails though then we can also whitelist the conflicting constants to not be checked.

[wezm]

Merged into #950