[Bug libstdc++/93502] std::regex_match uses stack space proportional to input string length

[avi@cloudius-systems.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93502

--- Comment #6 from Avi Kivity <avi@cloudius-systems.com> ---
Even if match_results stores a copy of the matching string, it would be stored
on the heap and only pointers would be stored on the stack. So the stack
overflow comes from recursion, not because of the delegation to the overload
that creates the match_results.