[PATCH] Add compatibility <sys/io.h>

[Bruce Evans]

On Sun, 11 Mar 2012, Adrian Chadd wrote:

> I agree we should move them out of the namespace. I'd even suggest
> prefixing them with something BSD specific, as two underscores may not
> be enough of a hint.

No, they are already outside of the user namespace.  cpufunc.h is a
kernel header that just happens to be abusable in userland.  Though
I originally intended it to be usable in userland.  2 underscores
would make any use undefined, but no more than most uses already are.

> That requires some sweeping changes of userland code, but I think it's
> for the best.

This would be mostly churn in the downwards direction.

I just checked the API in old DOS compilers.  In Turbo C it is:

     #include <dos.h>
     void outportb(int portid, unsigned char value);

     [outportb is normally a macro that expands to an inline asm function.]

So there is no conflict with this API, since its name is different.

Bruce