Motivation for this change

Update to latest upstream wolfssl version.

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux (Fedora 24)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip" (NOTE: no packages depend on wolfssl - see below!)
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

No package currently depends on wolfssl, so for testing I recompiled curl against wolfssl using the following shell.nix:

with import <nixpkgs> {};
let
  curlwolfssl = (curl.override {
    openssl = wolfssl;
  }).overrideDerivation (oldAttrs: {
    configureFlags = oldAttrs.configureFlags ++ [
      "--with-cyassl=${wolfssl}"
    ];
  });
in
{
  my-env = stdenv.mkDerivation {
    name = "my-env";
    buildInputs = [
      curlwolfssl
    ];
  };
}

I tested the resulting curl binary and compared its output against my local curl binary provided by Fedora:

curl -2 https://nixos.org
curl https://nixos.org > 1.txt
/usr/bin/curl https://nixos.org > 2.txt
diff 1.txt 2.txt

The first line gives an error message "curl: (35) CyaSSL does not support SSLv2" confirming that CyaSSL - which is the old name for wolfssl still referred to by curl - is indeed used. Diff of output of local curl and this new curl shows identical outputs as expected.