anchor.diff:    nativeBuildInputs = [ autoreconfHook ];
   
     # tcmalloc uses libunwind in a way that works correctly only on non-ARM linux
  -  buildInputs = stdenv.lib.optional (stdenv.isLinux && !(stdenv.isAarch64 || stdenv.isAarch32)) libunwind;
  +  buildInputs = lib.optional (stdenv.isLinux && !(stdenv.isAarch64 || stdenv.isAarch32)) libunwind;
   
     # Disable general dynamic TLS on AArch to support dlopen()'ing the library:
     # https://bugzilla.redhat.com/show_bug.cgi?id=1483558
  -  configureFlags = stdenv.lib.optional (stdenv.isAarch32 || stdenv.isAarch64)
  +  configureFlags = lib.optional (stdenv.isAarch32 || stdenv.isAarch64)
       "--disable-general-dynamic-tls";
   
  -  prePatch = stdenv.lib.optionalString stdenv.isDarwin ''
  +  prePatch = lib.optionalString stdenv.isDarwin ''
       substituteInPlace Makefile.am --replace stdc++ c++
       substituteInPlace Makefile.in --replace stdc++ c++
       substituteInPlace libtool --replace stdc++ c++
     '';
   
  -  NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.isDarwin
  +  NIX_CFLAGS_COMPILE = lib.optionalString stdenv.isDarwin
       "-D_XOPEN_SOURCE";
   
     # some packages want to link to the static tcmalloc_minimal
  
positive.code: 
    enableParallelBuilding = true;
  
    meta = with stdenv.lib; {
      homepage = "https://github.com/gperftools/gperftools";
      description = "Fast, multi-threaded malloc() and nifty performance analysis tools";
      platforms = with platforms; linux ++ darwin;
  
negative.code: { stdenv, lib, fetchurl, fetchpatch, autoreconfHook, libunwind }:
  
  stdenv.mkDerivation rec {
    name = "gperftools-2.8";
  