Thank you! I will merge it in 24 hours from now, and after this, if the package that requires byacc is found once more, please ping me and I will try to fix it. I believe that whatever method the termux-package-builder image uses to build such a hypothetical byacc-depending package should be adapted to on-device builds as well, for more consistency.

There are basically also some other mismatches between setup-termux.sh and setup-ubuntu.sh other than bison/byacc that need to be fixed separately, but because it's hard to precisely identify and create solutions for all of them at once, I would like to do them one at a time, so I am keeping this specific PR focused on bison/byacc.

In the repository, there are only two packages that reference byacc, zmap and nethack. zmap builds on-device pretty much fine after this change (with relation to byacc/bison), but nethack does actually get an error when building on-device that has a cause in the vicinity of its bison patch: make: lex: No such file or directory. The root cause of the problem is actually that two of nethack's patches should be .beforehostbuild patches so that they are applied during the on-device host-build to solve compilation errors, which does technically include making sure it always calls bison -y as intended instead of yacc (which is otherwise, after this change, a wrapper around bison -y). Therefore, for completeness, I will add a commit fixing on-device building of nethack into this PR.