No longer installs pcre2, which is built from source later on.
CMake is only installed if a recent version (3.16) is not found.
Jansson install cannot be removed yet as the Avro build requires
it.
VM should have 8 cores to make build faster in GCloud.
To get rid of ssfs between build hosts the build step
and upgrade test step are separated as well as
repository discriåtion generation
In CentOS8 some -devel packages are moved to PowerTools repository which
is disabled by default. install_build_depends now checks if this repo
is in the repolist then add enablerepo=PowerTools to the yum command
Installation of Docker is removed from build script because it is done
in the not very reliable way and can fail and cause build failure.
E.g. this installation causes conflict with existing Docker.
Checking presence of 'apt', 'yum' or 'zypper' command is not very
reliable way to determine package manager type.
E.g. OpenSUSE 25 has 'apt' which is wrapper over 'zypper' or rpm tools
can be installed on Ubuntu.
More relible way is to check /etc/*-release file and if it is not
availabe try to check presence of apt, yum or zypper
In Ubuntu Bionic there is need to update libssl which causes system services restart
and apt asks user to allow this restart. It cases build script to hang and build fails due to timeout.
Additional dpkg options and DEBIAN_FRONTEND=noninteractive solves the problem
The Avro libraries appear to sometimes overwrite the CMake
variables. Patching out the code that looks for the libraries should
prevent the library from ever being linked against the snappy libraries.
The script generates files owned by root so it needs to be removed with
sudo. As the removal of the directory is the last command, its failure
causes the script to fail.
