Specifically:
LLCoros::Mutex means boost::fibers::mutex
LLCoros::LockType means std::unique_lock<boost::fibers::mutex>
LLCoros::ConditionVariable means boost::fibers::condition_variable
LLCoros::cv_status means boost::fibers::cv_status
So as not to drag in all of boost::fibers::mutex.hpp or condition_variable.hpp
for each consumer of llcoros.h, instead #define LLCOROS_MUTEX_HEADER and
LLCOROS_CONDVAR_HEADER. Those who need them can #include the relevant macro.
Update llcond.h and llthreadsafequeue.h accordingly.
Also isClosed() and explicit operator bool() to detect closed state.
close() causes every subsequent pushFront() to throw
LLThreadSafeQueueInterrupt. Once the queue is drained, it causes popBack() to
throw likewise.
This also introduces LLContinueError for exceptions which should interrupt
some part of viewer processing (e.g. the current coroutine) but should attempt
to let the viewer session proceed.
Derive all existing viewer exception classes from LLException rather than from
std::runtime_error or std::logic_error.
Use BOOST_THROW_EXCEPTION() rather than plain 'throw' to enrich the thrown
exception with source file, line number and containing function.
Callum Prentice