You will need a version of Coq and various other tools supported by
CompCert v3.6. If you are using opam (recommended),
the following works as of 2020-03-06:
$ opam init
$ opam install coq.8.9.1 menhir.20200211
You can then clone the git repository using the following command:
$ git clone https://github.com/CertiKOS/rbgs.git
Our configure script will take care of retreiving the git submodule
for Coqrel and CompCertO, and will configure them:
$ cd rbgs
$ ./configure
At this point make sure there were no error messages. In particular if your versions of Coq, Menhir, etc. are not suitable to build CompCert, this is when things will break.
If the configuration was successful you should be able to build the
development using make. We recommend using the -jN option to enable
parallel jobs as CompCert will take a while to build otherwise.
For example on my 8-cores machine:
$ make -j8