[Bug libstdc++/64967] New: [5 Regression] Bootstrap fails due to errors in libstdc++ sources with `--enable-symvers=gnu-versioned-namespace'

["ai.azuma at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64967

            Bug ID: 64967
           Summary: [5 Regression] Bootstrap fails due to errors in
                    libstdc++ sources with
                    `--enable-symvers=gnu-versioned-namespace'
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ai.azuma at gmail dot com

Compile errors occur in stage 1 build of libstdc++ when trying to build GCC
5-20150201 with the following commands on an x86_64-unknown-linux-gnu machine
(Ubuntu 14.04 LTS):

  $ $SRCDIR/configure --enable-languages=c,c++
--enable-symvers=gnu-versioned-namespace
  $ make

The actual error messages are too long to paste here, but the very beginning of
them are:

/home/cryolite/work/gcc-bugs/20150207/objdir/./gcc/xgcc -shared-libgcc
-B/home/cryolite/work/gcc-bugs/20150207/objdir/./gcc -nostdinc++
-L/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/src
-L/home/cryolit
e/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
-L/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/libsupc++/.libs
-B/usr/local/x86_64-unknown-linux-gnu/bin/ -B/usr/local/x86
_64-unknown-linux-gnu/lib/ -isystem /usr/local/x86_64-unknown-linux-gnu/include
-isystem /usr/local/x86_64-unknown-linux-gnu/sys-include    -x c++-header
-nostdinc++ -g -O2 -D_GNU_SOURCE 
-I/home/cryolite/work/gcc-bugs/20150207/objdir/x86_6
4-unknown-linux-gnu/libstdc++-v3/include/x86_64-unknown-linux-gnu
-I/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include
-I/home/cryolite/work/gcc-bugs/20150207/gcc-5-20150201/libstdc++-v3/libsupc++
-O2
 -g -std=gnu++0x
/home/cryolite/work/gcc-bugs/20150207/gcc-5-20150201/libstdc++-v3/include/precompiled/stdc++.h
\
        -o x86_64-unknown-linux-gnu/bits/stdc++.h.gch/O2ggnu++0x.gch
In file included from
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/ios:38:0,
                 from
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/istream:38,
                 from
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/sstream:38,
                 from
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/complex:45,
                 from
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/ccomplex:38,
                 from
/home/cryolite/work/gcc-bugs/20150207/gcc-5-20150201/libstdc++-v3/include/precompiled/stdc++.h:52:
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/iosfwd:147:11:
error: âbasic_stringbufâ does not name a type
   typedef basic_stringbuf<char>  stringbuf;
           ^
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/iosfwd:150:11:
error: âbasic_istringstreamâ does not name a type
   typedef basic_istringstream<char>  istringstream;
           ^
/home/cryolite/work/gcc-bugs/20150207/objdir/x86_64-unknown-linux-gnu/libstdc++-v3/include/iosfwd:153:11:
error: âbasic_ostringstreamâ does not name a type
   typedef basic_ostringstream<char>  ostringstream;
           ^
(snip)

Bootstrap succeeds when `--enable-symvers=gnu-versioned-namespace' is unset.