checker: require unsafe for Struct(voidptr) casts

vlib/sync/pool/pool.v

@@ -118,13 +118,13 @@ fn process_in_thread(mut pool PoolProcessor, task_id int) {
 // get_item - called by the worker callback.
 // Retrieves a type safe instance of the currently processed item
 pub fn (pool &PoolProcessor) get_item[T](idx int) T {
-	return *(&T(pool.items[idx]))
+	return unsafe { *(&T(pool.items[idx])) }
 }
 
 // get_result - called by the main thread to get a specific result.
 // Retrieves a type safe instance of the produced result.
 pub fn (pool &PoolProcessor) get_result[T](idx int) T {
-	return *(&T(pool.results[idx]))
+	return unsafe { *(&T(pool.results[idx])) }
 }
 
 // get_results - get a list of type safe results in the main thread.
@@ -140,7 +140,7 @@ pub fn (pool &PoolProcessor) get_results[T]() []T {
 pub fn (pool &PoolProcessor) get_results_ref[T]() []&T {
 	mut res := []&T{cap: pool.results.len}
 	for i in 0 .. pool.results.len {
-		res << &T(pool.results[i])
+		res << unsafe { &T(pool.results[i]) }
 	}
 	return res
 }