please add scandir, alphasort, versionsort

[Michael Haubenwallner]

Hi,

As far as I can search, scandir and alphasort are candidates for the
next Single Unix Specification (post v3), and their usage is growing.

On Solaris for example, they are available starting with Solaris 10, but
I have the need to port some package to Solaris 8 and 9.

So I'm wondering if there is another reason than "missing resource" to
not have those functions in gnulib? Can I help somehow?

Thanks!

/haubi/