Restore neuron-search static binary fix, properly

[srid]

Revert #431 and fix project.nix to propagate former neuron-search build dependencies to neuron.

[srid]

Closing per https://neuron.zettel.page/next ... to further discuss this idea, in the context of Emanote, post here.

[srid]

Re-opening because this seems worth addressing for the plain 'cabal install' case; see #658 (reply in thread)