anchor.diff:  
     src = fetchurl {
       url = "mirror://gnupg/gnutls/v3.7/gnutls-${version}.tar.xz";
  -    sha256 = "1y0xi8cabh7i0lgka658qmdhjngkm29v4acq9brcjlnjj4ka5qj9";
  +    sha256 = "0vxcbig87sdc73h58pmcpbi4al1zgcxid1jn67mhcpna7sbdfxrp";
     };
   
     outputs = [ "bin" "dev" "out" "man" "devdoc" ];
  
positive.code:   #  - trust-store: default trust store path (/etc/ssl/...) is missing in sandbox (3.5.11)
    #  - psk-file: no idea; it broke between 3.6.3 and 3.6.4
    # Change p11-kit test to use pkg-config to find p11-kit
    postPatch = lib.optionalString (lib.versionAtLeast version "3.4") ''
      sed '2iecho "name constraints tests skipped due to datefudge problems"\nexit 0' -i tests/cert-tests/name-constraints
    '' + lib.optionalString (lib.versionAtLeast version "3.6") ''
      sed '2iexit 77' -i tests/{pkgconfig,fastopen}.sh
      sed '/^void doit(void)/,/^{/ s/{/{ exit(77);/' -i tests/{trust-store,psk-file}.c
      sed 's:/usr/lib64/pkcs11/ /usr/lib/pkcs11/ /usr/lib/x86_64-linux-gnu/pkcs11/:`pkg-config --variable=p11_module_path p11-kit-1`:' -i tests/p11-kit-trust.sh
  
negative.code: 
  assert guileBindings -> guile != null;
  let
    version = "3.7.1";
  
    # XXX: Gnulib's `test-select' fails on FreeBSD:
    # https://hydra.nixos.org/build/2962084/nixlog/1/raw .
  