anchor.diff:  
     src = fetchurl {
       url = "mirror://gcc/releases/gcc-${version}/gcc-${version}.tar.xz";
  -    sha256 = "1la2yy27ziasyf0jvzk58y1i5b5bq2h176qil550bxhifs39gqbi";
  +    sha256 = "13ygjmd938m0wmy946pxdhz9i1wq7z4w10l6pvidak0xxxj9yxi7";
     };
   
     inherit patches;
  
positive.code:         sha256 = ""; # TODO: uncomment and check hash when available.
        }) */
        ++ optional langAda ../gnat-cflags.patch
        ++ optional langAda (fetchpatch {
          name = "gnat-glibc-234.diff";
          url = "https://github.com/gcc-mirror/gcc/commit/331763de7d4850702a0f67298f36017c73cdb103.diff";
          sha256 = "eS4B7vJasnv2N+5v5yB8/iDpKPX8CJDAy2xabWWj+aU=";
        })
        ++ optional langD ../libphobos.patch
        ++ optional langFortran ../gfortran-driving.patch
        ++ optional (targetPlatform.libc == "musl" && targetPlatform.isPower) ../ppc-musl.patch
  
        # Obtain latest patch with ../update-mcfgthread-patches.sh
        ++ optional (!crossStageStatic && targetPlatform.isMinGW) ./Added-mcf-thread-model-support-from-mcfgthread.patch
  
        ++ [ ../libsanitizer-no-cyclades-9.patch ];
  
      /* Cross-gcc settings (build == host != target) */
      crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
  
negative.code: with builtins;
  
  let majorVersion = "9";
      version = "${majorVersion}.5.0";
  
      inherit (stdenv) buildPlatform hostPlatform targetPlatform;
  
      patches =
        [ ]
        ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
        ++ optional targetPlatform.isNetBSD ../libstdc++-netbsd-ctypes.patch
        ++ optional noSysDirs ../no-sys-dirs.patch
  