- enables rpm builds to occur on all RPM distros
- s390x on Ubuntu 2004 required g++-10, but the build system was overriding the CXX environment variable. This removes the override.
- not all RPM builders have scons, and its not needed any more. Easy to remove requirement.
dpkg isn't in the buiders, however dpkg-buildpackage which is used is
The success of these can be seen in the dev environment where these have been merged*.
Note *: excludes first one which may be merged by the time this is looked at - https://github.com/vladbogo/galera/pull/4