The DEPEND variable in the amd64 architecture only lists gnuchess as a build dependency, but uses texi2html in the build process. "texi2html" should be added to the DEPEND variable.
make check, as coded in the Makefile, does not make a test, but just build some docs. It fails during that, and documentation is always built during a complete emerge. So I RESTRICT the test phase so is never run for this ebuild.
