New comment by eli-schwartz on void-packages repository

https://github.com/void-linux/void-packages/pull/44663#issuecomment-1619380470

Comment:
Prior art: https://devmanual.gentoo.org/eclass-reference/meson.eclass/index.html#lbAF

meson_use is equivalent to vopt_bool

meson_feature is equivalent to the proposed vopt_feature

They, too, do not support defining it to auto. A Gentoo USE flag is either enabled or disabled, and besides they explicitly want to enforce that automagic dependencies do not happen, since they don't build in chroots/containers. :D