See also LogonUbuntu.
Debian 8 -> 9: libpng12
Autumn 2016:
After upgrading my Debian 8 “jessie” system to Debian 9 “stretch”, I found that libpng12 has been removed from the repos for libpng16. Because clim requires libpng12, the solution for me was to add ‘jessie’ to my sources list and then install libpng12-0.
For example, I track debian testing, which entails my upgrade to “stretch” when “jessie” went stable. So, I had to add “stable” back to my sources in order to see packages only in “jessie”.
deb http://ftp.us.debian.org/debian testing main contrib non-free
deb-src http://ftp.us.debian.org/debian testing main contrib non-free
deb http://ftp.us.debian.org/debian stable main contrib non-free
deb-src http://ftp.us.debian.org/debian stable main contrib non-free
deb http://ftp.debian.org/debian/ testing-updates main contrib non-free
deb-src http://ftp.debian.org/debian/ testing-updates main contrib non-free
deb http://ftp.debian.org/debian/ stable-updates main contrib non-free
deb-src http://ftp.debian.org/debian/ stable-updates main contrib non-free
After that apt-get update and then the missing package is available:
jcrowgey@quercus:~$ apt-cache search libpng12
libpng12-0 - PNG library - runtime
libpng12-dev - PNG library - development
libpng3 - PNG library - runtime
After sudo apt-get install libpng12-0, logon functionality is restored.
This mailing list thread contains some discussion including the error logs observed: http://lists.delph-in.net/archives/developers/2016/002334.html
Update 06-10-2016: oe added libpng12-0 and a handful of other shared libs to the logon tree, so this issue may not exist anymore.
Last update: 2016-10-06 by JoshuaCrowgey [edit]