src/third_party/s2/s2regioncoverer.cc:116:10: error: destination for this 'memset' call is a pointer to class containing a dynamic class 'S2Cell'; vtable pointer will be overwritten
      [-Werror,-Wdynamic-class-memaccess]
  memset(candidate, 0, size);
  ~~~~~~ ^
src/third_party/s2/s2regioncoverer.cc:116:10: note: explicitly cast the pointer to silence this warning
  memset(candidate, 0, size);
         ^
         (void*)