@@ -13,11 +13,11 @@
  * file.
  */
 
 #include "objfw-defs.h"
 
-#include "platform.h"
+#import "macros.h"
 
 #if defined(OF_HAVE_PTHREADS)
 # include <pthread.h>
 typedef pthread_once_t OFOnceControl;
 # define OFOnceControlInitValue PTHREAD_ONCE_INIT
@@ -26,10 +26,12 @@
 # define OFOnceControlInitValue 0
 #elif defined(OF_AMIGAOS) || !defined(OF_HAVE_THREADS)
 typedef int OFOnceControl;
 # define OFOnceControlInitValue 0
 #endif
+
+OF_ASSUME_NONNULL_BEGIN
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 /**
@@ -42,5 +44,7 @@
  */
 extern void OFOnce(OFOnceControl *control, void (*function)(void));
 #ifdef __cplusplus
 }
 #endif
+
+OF_ASSUME_NONNULL_END