Without the change the build fails on `master` as
https://hydra.nixos.org/build/249126465:
support/lockedpool.cpp: In member function 'void Arena::free(void*)':
support/lockedpool.cpp:102:20: error: 'runtime_error' is not a member of 'std'
102 | throw std::runtime_error("Arena: invalid or double free");
| ^~~~~~~~~~~~~