You found the right link with carl: it should take care of providing newer crypto for HTTPS for any browser (as it works as proxy).
The problem is not compiling TLS (or any other "modern" web feature), the problem is CPU as most of them are closer and closer to virtualization (just try VirtualPC as a refresher).
Please keep in mind that even with carl running locally on your Mac, you will have 2 potential challenges:
- JavaScript features supported or not
- new file format (images/videos) along with other browser features not present in Classilla (WebAssembly? WebRTC? WebGL? ...)
Happy browsing (as there is still lots that are reachable and efforts to keep/make retro-accessible sites like this one
).