hashtable: Drop when building inside CMake
CMake now builds as C++11 or higher and uses unordered_{map,set}
instead of hash_{map,set}. Skip providing KWSys hashtable to it
since it uses features deprecated by C++17.
System updates will be applied on January 22st between 0900 AM and 1200 PM, EST (UTC-05:00). This site may have intermittent downtime during that time.
CMake now builds as C++11 or higher and uses unordered_{map,set}
instead of hash_{map,set}. Skip providing KWSys hashtable to it
since it uses features deprecated by C++17.