* need to upgrade our custom packages to current standards
* switch those packages from CDBS to dh
* re-build on Trixie and upgrade the Lumiera DEB-Depot
After these (in detail quite expensive) preparations,
build with Scons and GCC-14 can be started.
Fix some further (basically trivial) compile problems,
uncovered by the improved type checking of modern compilers.
Note: a tremendous amount of warnings (and depreciations) is
also indicated, which will be addressed later....