For those running the 64-bit version of Slackware, I keep making available multilib versions of Slackware’s 64-bit gcc and glibc packages. Yesterday, gcc in slackware-current was updated to version 4.4.3, so here they are.
You can get them here: http://slackware.com/~alien/multilib/13.1/ (The “13.1” may or may not be the version of the next Slackware release, I just needed to give that directory a name).
For detailed instructions about what multilib means to the 64-bit Slackware and how you can add it, read this wiki article: http://alien.slackbook.org/dokuwiki/doku.php?id=slackware:multilib
Have fun! Eric