Well, since I solved the problem, I do not need to install bison instead of yacc...
However, it is stated in the download page that:
Download the source code and build using make. You'll need a c++ compiler, flex (not lex), yacc (bison works too) and the libpng graphics library. Most of this should be installed or easily available on any modern operating system distribution. See the README.txt file in the source for build and run instructions.
We should change that note. Yacc is a mess. There are many variants with different options and capabilities. The makefile works for Bison and may work for some versions of yacc, but it may not.