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

[csaba_22 at yahoo dot co.uk]

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

            Bug ID: 86513
           Summary: ostringstream default constructor missing from
                    libstdc++
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: csaba_22 at yahoo dot co.uk
  Target Milestone: ---

$ svn info ../trunk/
Path: ~/wk/GCC99/trunk
Working Copy Root Path: ~/wk/GCC99/trunk
URL: https://gcc.gnu.org/svn/gcc/trunk
Relative URL: ^/trunk
Repository Root: https://gcc.gnu.org/svn/gcc
Repository UUID: 138bc75d-0d04-0410-961f-82ee72b054a4
Revision: 262551
Node Kind: directory
Schedule: normal
Last Changed Author: rguenth
Last Changed Rev: 262551
Last Changed Date: 2018-07-11 09:08:54 +0200 (Wed, 11 Jul 2018)

After building and running 'make install'

$ g++-99 -v
Using built-in specs.
COLLECT_GCC=g++-99
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../trunk/configure --program-suffix=-99
--enable-version-specific-runtime-libs --enable-languages=c,c++,lto :
(reconfigured) ../trunk/configure --program-suffix=-99
--enable-version-specific-runtime-libs --enable-languages=c,c++,lto --no-create
--no-recursion
Thread model: posix
gcc version 9.0.0 20180711 (experimental) (GCC) 


$ echo _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT |
c++filt 
std::__cxx11::basic_ostringstream<char, std::char_traits<char>,
std::allocator<char> >::basic_ostringstream()@PLT

$ $ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.so | grep
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT
(no output)
$ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.a | grep
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT
(no output)
$ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.a | grep
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1E
0000000000000000 W
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1EOS4_
0000000000000000 W
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1ERKNS_12basic_stringIcS2_S3_EESt13_Ios_Openmode
0000000000000000 W
_ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1ESt13_Ios_Openmode

GCC is currently unusable for any program trying to use ostringstream: I get a
bunch of

undefined reference to `std::__cxx11::basic_ostringstream<char,
std::char_traits<char>, std::allocator<char> >::basic_ostringstream()'

errors.