anchor.diff:  in
   
   stdenv.mkDerivation rec {
  -  srcVersion = "jul19a";
  -  version = "20190701_a";
  +  srcVersion = "sep19a";
  +  version = "20190901_a";
     pname = "gildas";
   
     src = fetchurl {
  
positive.code: { stdenv, fetchurl, gtk2-x11 , pkgconfig , python27 , gfortran , lesstif
  , cfitsio , getopt , perl , groff , which
  }:
  
  let
  
negative.code:     # source code of the previous release to a different directory
      urls = [ "http://www.iram.fr/~gildas/dist/gildas-src-${srcVersion}.tar.xz"
        "http://www.iram.fr/~gildas/dist/archive/gildas/gildas-src-${srcVersion}.tar.xz" ];
      sha256 = "0l4jfzzxp1ab70a920qfbxiphgnc06m46wfwv0jlsq2mfk7cxac1";
    };
  
    enableParallelBuilding = true;
  
    nativeBuildInputs = [ pkgconfig groff perl getopt gfortran which ];
  
    buildInputs = [ gtk2-x11 lesstif cfitsio python27Env ]
      ++ stdenv.lib.optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [ CoreFoundation ]);
  
    patches = [ ./wrapper.patch ./clang.patch ./aarch64.patch ];
  
    NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.cc.isClang "-Wno-unused-command-line-argument";
  
    NIX_LDFLAGS = stdenv.lib.optionalString stdenv.isDarwin (with darwin.apple_sdk.frameworks; "-F${CoreFoundation}/Library/Frameworks");
  
    configurePhase=''
      substituteInPlace admin/wrapper.sh --replace '%%OUT%%' $out
  