[$] New features in C++26

ISO releases new C++language standards on a three-year cadence; now that it's beenmore than a year since the finalization ofC++23, we have a good idea of whatfeatures could be adopted forC++26 - although proposals canstill be submitted until January 2025. Of particular interest is the addition ofsupport forhazard pointers anduser-space read-copy-update (RCU).Even though C++26 is not yet a standard, many of the proposed features are alreadyavailable to experiment with in GCC or Clang.