[23:16:55] <pradyunsg> lazka: there is no "good" mechanism for overriding build dependencies like that. Part of the issue is that it'd need some sort of "design" work to figure out how exactly users should be allowed to pass that into pip, and that then determines what pip can do with it.
[23:17:24] <pradyunsg> In other words, it's a known usecase that has no "proper" solution at this time. ;)