with structuredAttrs lists will be bash arrays which cannot be exported
which will be a issue with some patches and some wrappers like cc-wrapper
this makes it clearer that NIX_CFLAGS_COMPILE must be a string as lists
in env cause a eval failure
Binaries of VST2 cannot be distributed without upstream permission
which we don't have and cant get. Until VST2 support can be
teased out more carefully, let's mark the package us unfree.