Hello again,
yes I did it, and it works well.
The latest package (afaik) is here - http://www.perzl.org/aix/index.php?n=Main.Syslog-ng
It's "only" 3.0.5, but works (well, not out-of-the-box, see below).
Prerequisites are glib2, gettext, bzip2, readline, eventlog and pcre, all available at the above site.
Be careful with gettext! It contains libintl.a, which is very touchy regarding its versions. But if you don't have installed it yet, no problem.
openssl is also a prerequisite, and that's a bit tricky, because openssl is now shipped with AIX, and versions do not always match.
You need 0.9.8 or higher, please check with "lslpp -l | grep openssl".
As for the source version -
syslog-ng's newest stable version is 3.1.2.
Compiling it from source is possible, of course. You will need the GNU compiler collection (gcc), and gmake for that. You can get it from perzl.org too (see above).
Once you installed syslog-ng and try to run it, don't forget to disable AIXs own syslog (disable it in /etc/rc.tcpip).
I'd suggest to download all rpms, to start installing the prerequisites, then syslog-ng, and to see how far you get. If there are issues during the above, please tell me, I will assist you.
wmp