Ok, I didn't have any problems building and installing the new version 0.20. I had built 0.19 on my system and it ran fine. However, when I start 0.20, I get the following message:
I think the Guichan you have installed on your system may have been compiled with a different compiler version than the one you're using to compile TMW. Make sure they are compatible, for example by (re)compiling Guichan yourself.