Github Copyright

https://help.github.com/articles/github-terms-of-service/

does forking means unsrestricted copying? I.e. I can take a github software without a license and use it without breaking law?

Yet this page say I'm not allowing to use that software:
http://stackoverflow.com/questions/5521080/can-i-use-the-code-in-a-github-project-which-does-not-have-a-license-specified

but I still believe forking is equivalent to copying.

I think the best route would be compiling and obfuscating the code you want to use, but that doesn't have license. When code gets compiled to x86, nobody'll ever by able to prove you've used it illegally.