anchor.diff:                 "./test/soltest -p -- --no-ipc --no-smt --testpath ../test";
   
     nativeBuildInputs = [ cmake ];
  -  buildInputs = [ boost z3 ];
  +  buildInputs = [ boost ]
  +    ++ stdenv.lib.optionals z3Support [ z3 ];
   
     outputs = [ "out" "dev" ];
   
  
positive.code: { stdenv, fetchzip, fetchFromGitHub, boost, cmake, z3 }:
  
  let
    version = "0.5.3";
  
negative.code:   cmakeFlags = [
      "-DBoost_USE_STATIC_LIBS=OFF"
      "-DBUILD_SHARED_LIBS=ON"
    ] ++ stdenv.lib.optionals (!z3Support) [
      "-DUSE_Z3=OFF"
    ];
  
    doCheck = stdenv.hostPlatform.isLinux && stdenv.hostPlatform == stdenv.buildPlatform;
  