I'm a huge fans of LibreOffice since i used it a lot in my work (mainly Impress for making presentations and Writer to make some reports). It's way much superior than the default Office Suite included in Slackware (KOffice, soon to be replaced by Calligra).
As we know, LibreOffice has reached version 3.5.1, but there is no 3.5.1 for Slackware-Current yet since the compilation process has changed drastically since previous 3.4.x and Eric is still working to make this version compilable on Slackware. It's not an easy job and i realized that since i used to compile OpenOffice in Windows and i understand the pain of compiling this kind of application. It requires a lot of time and effort to debug and a lot of trial and error with some luck.
Since there hasn't been any progress for the last 2-3 weeks, i offered him to help debugging the problem. He gave me his latest SlackBuild script and i tried to reproduce it on my desktop machine at home. I installed Apache Ant as one of the requirement to build LibreOffice and also Perl Module: Archive/Zip. Once it's finished, i started to build LibreOffice on that machine.
When i compiled OpenOffice.org in Windows in the past, it took me roughly 12-18 hours to complete due to a lot of trial and errors, but on this LibreOffice process, the SlackBuild script has been running for almost three days non stop and it still hasn't stopped yet (either completed or terminated prematurely). My desktop are not a very high end build machine, so it's normal to have longer time compared to Eric's.
Due to this process, i'm unable to upgrade my desktop yet to the latest Slackware-Current updates since it might interfere the compilation process (GCC, GLIBC, ccache, and binuntils are the packages that i think might be related to compilation).
Let's hope it will finish soon enough with good results at the end so that my time is not wasted and LibreOffice package for Slackware will be available in the short time.
Meanwhile, if you are eager to use LibreOffice 3.5.1, you can use Niels Horn's package which is basically a re-packaging of the LibreOffice binary package