Is changeable protocol (HTTPS) accessing github??

phpenv/phpenv is using protocol of git(9418) at the following actions:

* submodules (.gitmodules)
* clone php-src (libexec/phpenv-install)

However protocol of git is often blocked by corporate firewalls

Does not change the protocol of HTTPS?

If you agree to this proposal, I'll send [PR](https://github.com/nishigori/phpenv/commit/faa254b)


Please see more: [The Git Protocol >> The Cons - git-scm.com - ](http://git-scm.com/book/ch4-1.html#The-Git-Protocol)