anchor.diff:    gerbil = callPackage ../development/compilers/gerbil { stdenv = gccStdenv; };
     gerbil-unstable = callPackage ../development/compilers/gerbil/unstable.nix { stdenv = gccStdenv; };
   
  -  gccFun = callPackage ../development/compilers/gcc/8;
  -  gcc = gcc8;
  +  gccFun = callPackage ../development/compilers/gcc/9;
  +  gcc = gcc9;
     gcc-unwrapped = gcc.cc;
   
     gccStdenv = if stdenv.cc.isGNU then stdenv else stdenv.override {
  
positive.code:   flatpak-builder = callPackage ../development/tools/flatpak-builder { };
  
    fltrdr = callPackage ../tools/misc/fltrdr {
      stdenv = gcc8Stdenv;
      icu = icu63;
    };
  
  
negative.code: 
    fcitx-configtool = callPackage ../tools/inputmethods/fcitx/fcitx-configtool.nix { };
  
    fcppt = callPackage ../development/libraries/fcppt { };
  
    fcrackzip = callPackage ../tools/security/fcrackzip { };
  
  