[v3] define string::pop_back()

[Jonathan Wakely]

I first posted this a month ago, this adjusts the exports and moves
the tests under separate char and wchar_t directories as requested by
Paolo.

        * include/bits/basic_string.h (basic_string::at): Move adjacent to other
        overload.
        (basic_string::pop_back): Define.
        * include/debug/string (__gnu_debug::basic_string::pop_back): Likewise.
        * include/ext/vstring.h (__versa_string::pop_back): Likewise.
        * config/abi/pre/gnu.ver: Add new symbols.
        * testsuite/21_strings/basic_string/modifiers/char/pop_back.cc: New.
        * testsuite/21_strings/basic_string/modifiers/wchar_t/pop_back.cc: New.
        * testsuite/21_strings/basic_string/range_access.cc: Split to ...
        * testsuite/21_strings/basic_string/range_access/char/1.cc: Here and ...
        * testsuite/21_strings/basic_string/range_access/wchar_t/1.cc: Here.
        * testsuite/ext/vstring/modifiers/char/pop_back.cc: New.
        * testsuite/ext/vstring/modifiers/wchar_t/pop_back.cc: New.

Tested x86_64-linux, committed to trunk.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pop_back2.patch
Type: text/x-patch
Size: 15410 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20111107/d898aa67/attachment.bin>