The file is read by CMake (via new a json parser submodule) and
the web site generator and provides info on required clang and
gcc versions. This info will be expanded in future commits.

Goal is to have a single source of truth for versions infos and
maybe other requirements.

On CMake you access the info via `ogs.`-prefixed variables:

    ${ogs.minimum_version.gcc}

In Hugo you access the info via the new dataFile-shortcode:

    {{< dataFile "versions.minimum_version.gcc" >}}

Lars Bilke authored 5 years ago and Dmitry Yu. Naumov committed 5 years ago

Before: installation via pip.

Added note for Windows users to enable git symbolic links support.

On Ubuntu 18.04 the systems cmake package is at version 3.10 which
is too old.

6.2 is the minimum tested compiler by our CI (on envinf1).
6.5 is the default gcc 6 in Ubuntu 16.04 when using the ubuntu-toolchain-r/test PPA.