This feature allows to use static buffers (or from a pool of memory which is not
controlled by FreeRTOS).
In order to reduce the impact of the changes, the static feature has only been added
to the queus (and in consequence to the semaphores and the mutexes) and the tasks.
The Timer task is always dynamically allocated and also the idle task(s), which in the
case of the ESP-IDF is ok, since we always need to have dynamic allocation enabled.
The thread-local-storage feature in FreeRTOS attaches an application-usable array of pointers to a thread control block. These pointers usually point to a structure the thread allocates. When a thread gets (voluntarily or involuntarily) destroyed, this memory can leak. This merge adds a matching second array of user-settable pointers to destructor routines. As soon as the task gets cleaned up (which happens in the idle thread), the destructors get called and the memory can be freed.
See merge request !19