realpath can set errno on success

[Jerry James]

Hi Camm,

We recently had a build failure on Fedora that was traced back to
realpath() returning non-NULL AND setting errno to EINVAL.  The glibc
maintainers say:

"In general, POSIX specifies that errno only has a valid value after
an unsuccessful function call. glibc follows this policy."

In particular, the mbin() function added by the Version_2_6_13pre70
patch wraps massert() around a call to realpath().  Instead, the code
should check that realpath returns a non-NULL value.

Regards,
-- 
Jerry James
http://www.jamezone.org/