kernel: ignore overflow warnings in teams.cpp and threads.cpp

GCC's overflow checker gives a warning about the potential that the atomic
functions called in teams.cpp and threads.cpp will write to a null-pointer.
In this case, it is safe to assume that the values will never be null,
therefore these warnings can be safely ignored.

Relates to/fixes #17734

Change-Id: I777ff96f2812ed7d3ba57a46cad89ef6994cb08f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6643
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

src/system/kernel/team.cpp

@@ -4363,8 +4363,14 @@ _user_exit_team(status_t returnValue)
 
 	// Stop the thread, if the team is being debugged and that has been
 	// requested.
+	// Note: GCC 13 marks the following call as potentially overflowing, since it thinks team may
+	//       be `nullptr`. This cannot be the case in reality, therefore ignore this specific
+	//       error.
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wstringop-overflow"
 	if ((atomic_get(&team->debug_info.flags) & B_TEAM_DEBUG_PREVENT_EXIT) != 0)
 		user_debug_stop_thread();
+	#pragma GCC diagnostic pop
 
 	// Send this thread a SIGKILL. This makes sure the thread will not return to
 	// userland. The signal handling code forwards the signal to the main

src/system/kernel/thread.cpp

@@ -3796,7 +3796,13 @@ _user_block_thread(uint32 flags, bigtime_t timeout)
 		return waitStatus;
 
 	// nope, so wait
+	// Note: GCC 13 marks the following call as potentially overflowing, since it thinks `thread`
+	//       may be `nullptr`. This cannot be the case in reality, therefore ignore this specific
+	//       error.
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wstringop-overflow"
 	thread_prepare_to_block(thread, flags, THREAD_BLOCK_TYPE_USER, NULL);
+	#pragma GCC diagnostic pop
 
 	threadLocker.Unlock();