re PR libstdc++/42198 ([C++0x] Using std::thread without -pthread causes immediate crash)

2009-12-17  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/42198
	* src/thread.cc (thread::_M_start_thread): Throw system_error
	immediately if the thread system is inactive.

From-SVN: r155308