Just another day, debugging someone's installer

I like the installers that attempt (and then fail) to calculate what they need, and generate installation target names programmaticlly.
I know … I know… its an attempt to reduce the level of pain for some folks, as the algorithm works for some sets of inputs. But not mine. And mine are valid.
What we need is an –I_know_what_the_heck_I_am_asking_for_so_please_just_do_the_install switch. Or, I have their installer (thankfully non-terrible perl code) up in an editor to see if I can find the offensive part, and then I can patch it (and send them the patch).