There aren’t any instructions for building Grafx2 from sources on Linux (Ubuntu-derivatives, in particular), and although the process is not complicated or involved, I thought I’d document it, for posterity. Note that Grafx2 still uses SDL 1.x, not SDL2. If you try to build it after installing the SDL2 dev packages, you’re going to have a bad time. 

sudo apt-get install libsdl1.2-dev \
                     liblua5.1-0-dev \
                     libpng-dev \
                     libfontconfig1-dev \
                     libsdl-image1.2-dev \
                     libsdl-ttf2.0-dev

svn co svn://pulkomandy.tk/GrafX2

cd Grafx2/trunk/src
make

If you’re like me and you don’t like installing binaries into /usr/local, then you can install into ~/bin by creating a directory (say, Grafx2) and then copying ../bin and ../share into it. The Grafx2 binary is hard-coded to look for its auxilliary files in ../share.