I've been using Slackware Linux and its Vector derivative for some time now and I have found that Freepascal and Lazarus make a great programming combination.
Installing is not a problem. Download the stable build of Freepascal, untar it, and, as root install using the shell script. Simply a matter of writing ./install.sh and pressing enter.
After downloading the source file Lazarus is installed into your home folder by untaring it, opening a terminal in the folder and issuing the command, make clean all.
This is how it's done with the latest versions anyway.
I have had the previous version (2.2.2) of Freepascal installed for a while and I have had a problem compiling updated versions of Lazarus. The errors that came up involved GTK2 calls. I investigated updating GTK2 just in case, no need to apparently, I have the latest version. It was only when I updated to Freepascal 2.2.4 and then compiled Lazarus that the errors were conspicuous by their absense!
Just a word to the wise if you are having this problem.