Declare tStart and tFinish

[schlimmchen]

the variables tStart and tFinish are required if sleep support is enabled, independent of _TASK_TIMECRITICAL. however, they were guarded by _TASK_TIMECRITICAL as well.

this bug prevents building Scheduler_example19_Dynamic_Tasks_SelfDestruct.ino in particular.

[arkhipenko]

Pushed into testing branch as v3.8.4

[schlimmchen]

Thanks for looking at this PR and adopting it 😊

I saw you implemented the fix slightly differently. Just as an FYI I'd like to point out that tIdleStart is only used if both _TASK_TIMECRITICAL and _TASK_SLEEP_ON_IDLE_RUN are defined. However, tIdleStart is now declared already if only _TASK_TIMECRITICAL is defined. There will be a compiler warning (if -Wall or -Wunsued-variable is used) for users who only enable _TASK_SLEEP_ON_IDLE_RUN.

[arkhipenko]

Thanks for the comment. I will look into it!