Please include the static library in the release source tar-ball

[kekePower]

Hi. I'm hoping it would be possible to include the possibility to build the static library from the release tar-ball.

Downloaded version 0.7.0 and the Makefile differs from the Makefile from git, and guetzli_static.make is missing.

I would like to include it in Mageia Cauldron repository and had to create a very intrusive patch that isn't optimal.

TIA.

[coooliang]

4.Run the following command to build the binary in bin/Release/guetzli. If you installed using Homebrew simply use make