New review comment by Phicem on void-packages repository

https://github.com/void-linux/void-packages/pull/39984#discussion_r1002414642

Comment:
However if I do that (including tetgen binary directly into CalculiX-cgx package), I'm afraid I will have to define a custom do_build() function, since there are two independant makefile/cmake files. I could patch cgx makefile so that it calls tetgen makefile, but I don't find this very elegant.

An alternative is to keep tetgen in a separate sub-package called CalculiX-tetgen, using the tetgen version vendored by CalculiX.

In short, the solutions I see are:
1. single package with a custom do_build() function
2. single package with a patch on the makefile
3. keeping a separate subpackage called Calculix-tetgen

I don't know which one is the cleanest option. What do you think?