libstdc++/9580: basic_filebuf<> with custom traits_type fails to link

[Gabriel Dos Reis]

Paolo Carlini <pcarlini@unitus.it> writes:

|  > I'm tempted to see this as a bug in our library...
|  > Can someone recall me briefly why we can't make this work?
| 
| Probably we can! The bug was still in the open state, nobody had really
| looked at it and if there are no infrastructural serious impediments
| (can you confirm that?) probably someone (you? Benjamin? me?) will
| fix it soon!

This is something we should fix.  However I don't have necessary time
next week to work on it. I'm sorry.

-- Gaby