By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Use dontInstall instead of a no-op installPhase The coverage and report derivations populate $out directly in buildPhase, so the install phase is unnecessary. Replace the no-op `installPhase = "runHook preInstall; runHook postInstall"` (which only existed to suppress stdenv's default `make install`) with the idiomatic `dontInstall = true`.