anchor.diff:      "--disable-avx512"
       "--disable-avx-128-fma"
       "--disable-kcvi"
  -    (enFlag "altivec" (elem targetSystem platforms.powerpc-all) null)
  +    "--${boolEn (elem targetSystem platforms.powerpc-all)}-altivec"
       "--disable-vsx"
  -    (enFlag "neon" (elem targetSystem platforms.arm-all) null)
  +    "--${boolEn (elem targetSystem platforms.arm-all)}-neon"
       #--enable-armv8cyclecounter
  -    (enFlag "generic-simd128" (
  +    "--${boolEn (
         precision == "single"
  -      || precision == "double") null)
  -    (enFlag "generic-simd256" (
  +      || precision == "double")}-generic-simd128"
  +    "--${boolEn (
         precision == "single"
  -      || precision == "double") null)
  +      || precision == "double")}-generic-simd256"
       #--enable-mips-zbus-timer
       "--enable-fma"
  -    #(enFlag "mpi" (
  +    #"--${boolEn (
       #  mpi != null
       #  && (
       #    precision == "single"
       #    || precision == "double"
  -    #    || precision == "long-double")) null)
  +    #    || precision == "long-double"))}-mpi"  null)
       "--disable-fortran"
       "--enable-openmp"
       "--enable-threads"
  
positive.code: { stdenv
  , fetchurl
  
  , precision
  }:
  
negative.code:     "-fPIC"
    ];
  
    passthru = {
      srcVerification = fetchurl {
        inherit (src)
          outputHash
          outputHashAlgo
          urls;
        md5Url = map (n: "${n}.md5sum") src.urls;
        failEarly = true;
      };
    };
  
    meta = with lib; {
      description = "Library for Fast Discrete Fourier Transform";
      homepage = http://www.fftw.org/;
      license = licenses.gpl2Plus;
  