how to build with clang?

[piterzhang]

The README mentions using gcc to build the project, but many projects nowadays use clang for compilation. Personally, I have always used gcc, and I believe many others might also be unfamiliar with building the project using clang. It would be helpful if the README could include detailed instructions or a guide on how to build the project with clang.

[travisg]

Good idea! It's a bit mechanical right now, it needs to be a little smoother to be honest, which is when I was hoping to document it. But one way or another it should be written down.