Small suggestion about compiling git documentation.
URL: https://git-scm.com/book/en/v2/Getting-Started-Installing-Git

"Installing from Source" part:

In order to be able to add the documentation in various formats (doc, html, info), these additional dependencies are required (Note: users of RHEL and RHEL-derivatives like CentOS and Scientific Linux will have to enable the EPEL repository to download the docbook2X package):

$ sudo dnf install asciidoc xmlto docbook2X getopt
$ sudo apt-get install asciidoc xmlto docbook2x getopt

On a Debian Stretch 9.4 fresh install:

# apt-get install getopt
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package getopt

I was stucked a bit.
Why? Because package getopt is already installed:

# getopt --version
getopt from util-linux 2.29.2

• In order to avoid users to panic / loose time finding why we got this error, it might be usefull to add a sentence about this package?

Thanks for your awesome work anyway, great doc.