Errors in the Lua library produce longjmps.
The longjmp will not unwind the C++ stack.
In the new test, the lock was not being released, and the system was deadlocking in the next call that tried to lock the environment
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
(optional) Boost (version >= 1.54), we can
build Lean using boost::thread instead of std::thread. When using
Boost, Lean can modify the thread stack size.