Given the 64-bit timebase, add trylock_until to Mutex.
Naming is based on a combination of Mutex::trylock, Thread::wait_until,
and C++11 timed_mutex::try_lock_until.
pthreads and C11 use "timedlock", but that's not a good fit against our
existing trylock() and lock(timeout) - they have only absolute-time
waits, not relative.
To increase the similarity to C++11, add trylock_for - same parameters
as lock, but with the bool return value of trylock and trylock_until.
Add an assertion when convering status codes to booleans to check that
there are no non-timeout errors.
Various RTOS classes were storing their CMSIS-RTOS creation attribute
structure as a member, when it's not required after construction. Reduce
memory by eliminating this member.
Add the attribute flash to enable priority inheritance and robust mode.
The robust flag allows mutexes held by terminated threads to be
properly released.
Kevin Bracey
Martin Kojtal
Russ Butler
Bartek Szatkowski
Sam Grove
Christopher Haster