Unset NIX_LDFLAGS, stop-gap fixing "Argument list too long" errors

[ixmatus]

I suspect this doesn't correctly fix #132 but I did want to open a PR with our (Awake Security) temporary workaround so that anyone else with this problem can discover this solution and so that we can discuss whether this suffices or if we want to approach solving this with the suggested passAsFile approach.

Credit for this workaround goes entirely to @intractable (Joel Stanley).

[adnelson]

So at Narrative Science we ran into this issue but specifically with NODE_PATH. We found that just unsetting the environment variable doesn't always work, if the environment is already too large by the time the unset line is encountered, and the place where this happens is in the addNodePath bash function, which is defined as a setup hook for nodejs (and therefore invoked by all node packages).

So the solution we came up with was to patch ${stdenv}/setup with one that specifically ignored the addNodePath function, and add a builder argument to mkDerivation which invoked the patched version instead. Roundabout, but it got the job done... not sure if it would fix this behavior as well or if it's something desirable to do all the time.

[adnelson]

Can we get an example derivation (or set thereof) that causes this error? If I have some time I'd like to dive in and see what's going on.

[ixmatus]

I can concoct a failing case similar to the one we see with our project, I will have time to do that probably this weekend.