For C++11 std::ws changed to be an unformatted input function, meaning
it constructs a sentry and sets badbit on exceptions.
libstdc++-v3/ChangeLog:
* doc/xml/manual/intro.xml: Document LWG 415 change.
* doc/html/manual/bugs.html: Regenerate.
* include/bits/istream.tcc (ws): Create sentry and catch
exceptions.
* testsuite/27_io/basic_istream/ws/char/lwg415.cc: New test.
* testsuite/27_io/basic_istream/ws/wchar_t/lwg415.cc: New test.
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