File tg_owt-fix-nonnull.patch of Package tg_owt

--- a/src/api/task_queue/pending_task_safety_flag.h
+++ b/src/api/task_queue/pending_task_safety_flag.h
@@ -11,6 +11,13 @@
 #ifndef API_TASK_QUEUE_PENDING_TASK_SAFETY_FLAG_H_
 #define API_TASK_QUEUE_PENDING_TASK_SAFETY_FLAG_H_
 
+// Compatibility fix for abseil-cpp versions without Nonnull
+#ifndef ABSL_ATTRIBUTE_NONNULL
+#define ABSL_ATTRIBUTE_NONNULL(x)
+#endif
+#ifndef absl_Nonnull
+#define absl_Nonnull(x) x
+#endif
+
 #include <memory>
 
 #include "absl/functional/any_invocable.h"
@@ -73,7 +80,7 @@ class RTC_EXPORT PendingTaskSafetyFlag final {
   // attached to.
   void SetNotAlive();
   void SetAlive(
-      absl::Nonnull<TaskQueueBase*> attached_queue);
+      TaskQueueBase* attached_queue);
 
   const SequenceChecker& sequence_checker_for_test() const {
     return main_sequence_;
@@ -103,7 +110,7 @@ class RTC_EXPORT PendingTaskSafetyFlag final {
   PendingTaskSafetyFlag(const PendingTaskSafetyFlag&) = delete;
   PendingTaskSafetyFlag& operator=(const PendingTaskSafetyFlag&) = delete;
   explicit PendingTaskSafetyFlag(bool alive,
-                        absl::Nonnull<TaskQueueBase*> attached_queue)
+                        TaskQueueBase* attached_queue)
       : alive_(alive), main_sequence_(attached_queue) {}
 
   static constexpr FlagState kAlive = FlagState(true);