[png-mng-implement] New libpng ftp site at OSU-OSL

[Glenn Randers-Pehrson]

I'm pleased to announce a new ftp site for libpng tarball
distributions, thanks to Oregon State University's Open Software
Laboratory. It is able to deliver at a rate that is twenty or
more times as fast as ftp.simplesystems.org, and will
respond to http and https requests as well as anonymous
ftp requests.

https://ftp-osl.osuosl.org/pub/libpng
http://ftp-osl.osuosl.org/pub/libpng
ftp://ftp-osl.osuosl.org/pub/libpng

The history files are arranged differently. At
simplesystems, it was

pub/png/src
libpngNN
current *tar.xz, *tar.gz, *7z, *zip, *.asc
history
libpngNN
old *.tar.xz, *tar.gz, *7z, *zip, *.asc

pub/png-group/src
libpngNN
current beta and rc *.tar.gz. *.tar.xz, *.7z, *.zip
history
libpngNN
old beta and rc *.tar.gz. *.tar.xz, *.7z, *.zip

At OSU-OSL, it's

ftp/pub/libpng/src
libpngNN
current *tar.xz, *tar.gz, *7z, *zip, *.asc
beta
libpngNN
current beta *tar.xz, *tar.gz, *7z, *zip. *.asc
archive
xz
libpngNN
*.tar.xz, *.xz.asc
gz
libpngNN
*.tar.gz, *.gz.asc
7z
libpngNN
*.7z, *.7z.asc
zip
libpngNN
*.zip, *.zip.asc

I'm putting a link of the currently active files immediately into
the "archive" directory, so any particular version gets a
permanent home right away, instead of waiting until a new
version is released to move it into "history".

There's no distinguishing between "png" and "png-group"
as previously; instead the public releases, betas, and rcs
all appear together in the archive directory. But for navigation
convenience, the active releases also appear at the
top of the file structure in "libpngNN" and "beta" directories.

All archives have digital GPG signatures (*.asc) instead of
just the public releases.

If you manage a distro that is currently sending build scripts that
hit ftp.simplesystems.org, please revise your scripts to use
ftp-osl.osuosl.org instead.

Glenn