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.
A GitLab update will be applied on May 9th, between 8am and 10am, EDT (UTC-04:00). This site may have intermittent delays 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.