type-safety checks for fcntl and ioctl

[Pedro Giffuni]

Hello;

I had a try on adding the ioctl() and fcntl() clang attributes to our
system headers but failed miserably, apparently due to xlint issues:
...
fcntl.h(307): syntax error [249]
...

There is few documentation about this [1][2] so I am sharing the
link of my (simple but probably incomplete) experiment in case
someone feels like picking it up some day:
https://people.freebsd.org/~pfg/patches/fcntl-type-safety.diff

Regards,

Pedro.

References:
[1]
http://clang.llvm.org/docs/AttributeReference.html#type-safety-checking
[2]
http://hpc-ua.org/hpc-ua-12/files/proceedings/3.pdf