anchor.diff:  
     configureFlags = [
       "--with-blas-libs=-lopenblas"
  -    "--with-lapack-libs=-llapack"
       "--disable-optimization"
     ] ++ stdenv.lib.optionals (!optimize) [
       # disable SIMD instructions (which are enabled *when available* by default)
  
positive.code: 
    buildInputs = [
      givaro
      (liblapack.override {shared = true;})
      openblas
      gmpxx
      fflas-ffpack
  
negative.code: , givaro
  , pkgconfig
  , openblas
  , fflas-ffpack
  , gmpxx
  , optimize ? false # impure
  