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
If things build fine with `stdenvNoCC`, let them use that. If tools
might be prefixed, prepare for that, either by directly splicing or just
using the env vars provided by the wrapper setup-hooks.
Co-authored-by: Dmitry Kalinkin <dmitry.kalinkin@gmail.com>