the buildsystem will now pick up and link
all test cases according to the layer, e.g.
backend tests will automatically be linked
against the backend + library solely.
After removing the explicit locking, there is a small
race in case of a "floundering" (simulated) subsystem:
the starting context may go away before the child thread
actually teminates. I consider this a shortcoming of
this test fixture, which isn't intended to be an example
of a real world subsystem, but rather focusses on
error detection within the subsystem runner.
using new thread synchronization
Disabled further tests, making one after another working.
Some notes:
* currently running this leads to different outcomes on differnt runs,
there are some races/unsyncronized things left, to be investigated.
* I suggest to make Subsystems joinable, this prolly needs some work in
the error handling department (thread-wrapper.hpp too)
* using nonrecursive/waitable lock, recursive locks are have some bad
taste unless absolutely necessary
* after all a timed lock with polling is not the right approach to check
for subsystem shutdowns, I opted against thread cancelation because of
its programming overhead and complexity. We may refine this and allow
synchronous cancellation (with an approbiate thread flag) in some cases.
- clarify the meaning of run(true), run(fail), run(throw)
- do a real handshake between start() and the subsystem thread
- avoid accessing the SubsystenRunner after signalling termination
