anchor.diff:  , dyld ? null # TODO: should this be a setup-hook on dyld?
   , isGNU ? false, isClang ? cc.isClang or false, gnugrep ? null
   , hostPlatform, targetPlatform
  +, runCommand ? null
   }:
   
   with stdenv.lib;
  
positive.code:         ln -s $ldPath/${prefix}as $out/bin/${prefix}as
        fi
  
        wrap ${prefix}ld ${./ld-wrapper.sh} ''${ld:-$ldPath/${prefix}ld}
  
        if [ -e ${binutils_bin}/bin/${prefix}ld.gold ]; then
          wrap ${prefix}ld.gold ${./ld-wrapper.sh} ${binutils_bin}/bin/${prefix}ld.gold
        fi
  
        if [ -e ${binutils_bin}/bin/ld.bfd ]; then
          wrap ${prefix}ld.bfd ${./ld-wrapper.sh} ${binutils_bin}/bin/${prefix}ld.bfd
        fi
  
        export real_cc=${prefix}cc
  
negative.code:     ''
  
      + ''
        substituteAll ${preWrap ./setup-hook.sh} $out/nix-support/setup-hook.tmp
        cat $out/nix-support/setup-hook.tmp >> $out/nix-support/setup-hook
        rm $out/nix-support/setup-hook.tmp
  
  