[PATCH] Some code improvements (no functional change)

[Artyom Skrobov]

>> -- I think this shows a prominent tendency to have such guards in private
>> headers.
>
> Good point.  SGTM.
>
> Go ahead and add the guards if you have commit privileges, otherwise
> please repost the patch here and I'll commit it for you.

Thank you Duncan! The guards now committed as r210794

I appreciate your suggestion to split patches into separate review threads
in future.