Update code to version 2.2.0 - gcc patch (#1942440) (part 2/4)
    
    Description and changes for gcc11 patch has been added.
    Few cosmetic changes has been added/updated:
    
    * Compatibility patch for promethes-cpp dependency in histogram.cc file.
      This file is missing headers. gcc or new version of it require it
      specifically.
      This part of the patch can be removed with promethes-cpp dependency
      update in proxysql source code in the future.
    
      Tracking for this change in upstream needs to be resolved in future.
    
    * Custom swap command in mariadb-client dependency still needs to be
      renamed to avoid conflicts with native function.
    
      Tracking for this change in upstream needs to be resolved in future
      with mariadb-client devs.