# Pastebin zCdD9OXX
      mkDerivation rec {

...
        librarySystemDepends = [ portaudio ];

        shellHook = ''
          export C_INCLUDE_PATH = \
            ${stdenv.lib.makeSearchPathOutput "dev" "include" librarySystemDepends}
          export LIBRARY_PATH = \
            ${stdenv.lib.makeLibraryPath librarySystemDepends}
        '';
        FOO="foo";

      };