[Bug libstdc++/86513] ostringstream default constructor missing from libstdc++

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86513

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2018-07-14
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Have you done a clean build?

Those symbols were added last week, but if you are doing an incremental build
in an existing build tree you need to do 'make clean' in the libstdc++-v3 build
directory and then build again.

If you're using the subversion trunk you need to be prepared to do such things.