[Bug libstdc++/65042] gcc5 has a template depth problem that was fine in gcc4

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65042

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Trying to use the standard library with such a tiny limit is simply not going
to work. If it worked previously you got lucky, but if you need to raise the
limit now then that's what you need to do.

What's the purpose of enforcing such a tiny limit anyway?