AP_HAL_Linux: Thread: allow loose running thread

libraries/AP_HAL_Linux/Thread.cpp

@@ -40,6 +40,10 @@ void *Thread::_run_trampoline(void *arg)
     thread->_poison_stack();
     thread->_run();
 
+    if (thread->_auto_free) {
+        delete thread;
+    }
+
     return nullptr;
 }
 

libraries/AP_HAL_Linux/Thread.h

@@ -45,6 +45,8 @@ public:
 
     bool set_stack_size(size_t stack_size);
 
+    void set_auto_free(bool auto_free) { _auto_free = auto_free; }
+
     virtual bool stop() { return false; }
 
     bool join();
@@ -64,6 +66,7 @@ protected:
     task_t _task;
     bool _started = false;
     bool _should_exit = false;
+    bool _auto_free = false;
     pthread_t _ctx = 0;
 
     struct stack_debug {