[PATCH libpciaccess] common_interface.c: Use proper byteswap functions on APPLE systems

[shea at shealevy.com]

> On 08/29/11 00:53, shea at shealevy.com wrote:
>>
>> APPLE systems do not have <sys/endian.h>, they have
>> <architecture/byte_order.h> instead.
>
> Making libpciaccess work on MacOS is going to take a lot more than
> just fixing byte-swapping - are you doing a full port?
>
> --
> 	-Alan Coopersmith-        alan.coopersmith at oracle.com
> 	 Oracle Solaris Platform Engineering: X Window System
>
>

I'm working on it... Though mostly with the intent of "get things that
depend on it working" rather than using it directly in my own development.
This was just the minimum change needed to get it to build, I haven't yet
had a chance to test how it fails at runtime yet.

~Shea Levy