realpath(3): Upgrade to POSIX IEEE Std 1003.1-2008

realpath(3): Upgrade to POSIX IEEE Std 1003.1-2008

Recent updates to realpath implements some of the missing POSIX
functionality, but the requirement to allocate memory for the pointer
returned by the function when a null pointer is passed to the
resolved_path argument was missing.

The prototype changes in the following ways:
1.  The restrict type qualifier is added to both arguments
2.  The second argument changes from "char resolved[PATH_MAX]" to
    "char * resolved"

The new prototype is backwards-compatible with the old one.

This should bring realpath up to Open Group Specifications Issue 7
IEEE Std 1003.1-2008
http://pubs.opengroup.org/onlinepubs/9699919799/functions/realpath.html

Taken from:
FreeBSD SVN 206893 (20 APR 2010)
FreeBSD SVN 206898 (20 APR 2010)
FreeBSD SVN 217144 (08 JAN 2011)
FreeBSD SVN 227090 (04 NOV 2011)