Cannot install Zephir on Ubuntu 18.04

I followed the published process for installing Zephir, which worked perfectly, until I reached the ./install -c. At that point, I get "bash: ./install: No such file or directory". Yes, I did cd zephir. It appears that "git clone https://github.com/phalcon/zephir" worked but, it failed to download "install".

I have successfully installed the latest version of phalcon, with php5.6 on apache2.

So, help, please.