Adding something to my previous post: I'm not able to use GCC 4.7.1 atm, emerge and/or overlay aren't being updated for some reason... and edubart just refactored his code to use big new c++11 features that are available from GCC 4.7.1+...
As far as I remember, I had to compile boost 1.50, gimp3 (or smth) and OpenAL probably, also XOpenIM (from the X11 lib) won't work on my system because of some language thing, so that might be the problem for you, try debugging? You can find a list of packages you need over here:
otclient.info | Compiling on Linux