Finally ! After almost 6 months of betas and release candidates...
You can get it here :
http://thedoryenlibrary.appspot.com/
The documentation has also moved here :
http://roguecentral.free.fr/libtcod/1.4/doc/doc.php
I'll try to get an up-to-date version for linux 64bits as soon as possible.
I'll maintain the 1.4 branch with bugfix releases probably for quite a long time because the new 1.5 branch will break API compatibility. See the roadmap on libtcod's site for details.
I also wanted to thank all the developers who put their trust in libtcod for the recent 7DRL challenge. I'll soon put a brainstorming thread on libtcod's forum to get as much feedback as possible from this event and to put the 1.5 version on the right track to be even easier to use and more powerful.