* 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.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@181049
138bc75d-0d04-0410-961f-
82ee72b054a4