Sharing of bits/fcntl.h for Linux - some questions

[Roland McGrath]

> I might have misunderstood your suggestion, changing this is no problem,
> I 'll do it tomorrow. Any other suggestions?

I noticed a typo in a comment or two, but I presume those were just copied
over.  So double-check the copied text for those things.  I think we also
need to see at least one or two other machine-specific files adapted to be
clear on how it's fitting together.