bpo-34555: Fix incorrectly nested test for HAVE_LINUX_VM_SOCKETS_H

[mcduke]

Unnested the check for HAVE_LINUX_VM_SOCKETS_H, to be independent of HAVE_SOCKADDR_ALG. Also added indentation to the HAVE_SOCKADDR_ALG block to make it clearer where it starts and ends.

https://bugs.python.org/issue34555

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[benjaminp]

It would help to have a space after this line to make it symmetric with the line before the #endif.

[mcduke]

This makes sense, amended my pull request.

[benjaminp]

These ifdefs seem rather silly to me. If linux/if_alg.h exists, surely sys/socket.h is going to define AF_ALG and SOL_ALG, right?

[mcduke]

I don't know enough about this topic to be sure, but from a cursory search it appears to be a guideline in the Linux docs to include this block, in case of older header files that don't yet define these constants themselves.

[miss-islington]

Thanks @mcduke for the PR, and @benjaminp for merging it 🌮🎉.. I'm working now to backport this PR to: 3.7.
🐍🍒⛏🤖

[bedevere-bot]

GH-9029 is a backport of this pull request to the 3.7 branch.