Index: src/runtime/private.h
==================================================================
--- src/runtime/private.h
+++ src/runtime/private.h
@@ -16,166 +16,164 @@
 
 #include "config.h"
 
 #include "platform.h"
 
-#if defined(__has_feature) && __has_feature(nullability)
-# define OBJC_NONNULL _Nonnull
-# define OBJC_NULLABLE _Nullable
-#else
-# define OBJC_NONNULL
-# define OBJC_NULLABLE
+#if !defined(__has_feature) || !__has_feature(nullability)
+# ifndef _Nonnull
+#  define _Nonnull
+# endif
+# ifndef _Nullable
+#  define _Nullable
+# endif
 #endif
 
 struct objc_abi_class {
-	struct objc_abi_class *OBJC_NONNULL metaclass;
-	const char *OBJC_NULLABLE superclass;
-	const char *OBJC_NONNULL name;
+	struct objc_abi_class *_Nonnull metaclass;
+	const char *_Nullable superclass;
+	const char *_Nonnull name;
 	unsigned long version;
 	unsigned long info;
 	long instance_size;
-	void *OBJC_NULLABLE ivars;
-	struct objc_abi_method_list *OBJC_NULLABLE methodlist;
-	void *OBJC_NULLABLE dtable;
-	void *OBJC_NULLABLE subclass_list;
-	void *OBJC_NULLABLE sibling_class;
-	void *OBJC_NULLABLE protocols;
-	void *OBJC_NULLABLE gc_object_type;
+	void *_Nullable ivars;
+	struct objc_abi_method_list *_Nullable methodlist;
+	void *_Nullable dtable;
+	void *_Nullable subclass_list;
+	void *_Nullable sibling_class;
+	void *_Nullable protocols;
+	void *_Nullable gc_object_type;
 	long abi_version;
-	int32_t *OBJC_NONNULL *OBJC_NULLABLE ivar_offsets;
-	void *OBJC_NULLABLE properties;
+	int32_t *_Nonnull *_Nullable ivar_offsets;
+	void *_Nullable properties;
 };
 
 struct objc_abi_selector {
-	const char *OBJC_NONNULL name;
-	const char *OBJC_NULLABLE types;
+	const char *_Nonnull name;
+	const char *_Nullable types;
 };
 
 struct objc_abi_method {
 	struct objc_abi_selector sel;
-	IMP OBJC_NONNULL imp;
+	IMP _Nonnull imp;
 };
 
 struct objc_abi_method_list {
-	struct objc_abi_method_list *OBJC_NULLABLE next;
+	struct objc_abi_method_list *_Nullable next;
 	unsigned int count;
 	struct objc_abi_method methods[1];
 };
 
 struct objc_abi_category {
-	const char *OBJC_NONNULL category_name;
-	const char *OBJC_NONNULL class_name;
-	struct objc_abi_method_list *OBJC_NULLABLE instance_methods;
-	struct objc_abi_method_list *OBJC_NULLABLE class_methods;
-	struct objc_protocol_list *OBJC_NULLABLE protocols;
+	const char *_Nonnull category_name;
+	const char *_Nonnull class_name;
+	struct objc_abi_method_list *_Nullable instance_methods;
+	struct objc_abi_method_list *_Nullable class_methods;
+	struct objc_protocol_list *_Nullable protocols;
 };
 
 struct objc_abi_method_description {
-	const char *OBJC_NONNULL name;
-	const char *OBJC_NONNULL types;
+	const char *_Nonnull name;
+	const char *_Nonnull types;
 };
 
 struct objc_abi_method_description_list {
 	int count;
 	struct objc_abi_method_description list[1];
 };
 
 struct objc_abi_static_instances {
-	const char *OBJC_NONNULL class_name;
-	id OBJC_NULLABLE instances[1];
+	const char *_Nonnull class_name;
+	id _Nullable instances[1];
 };
 
 struct objc_abi_symtab {
 	unsigned long unknown;
-	struct objc_abi_selector *OBJC_NULLABLE sel_refs;
+	struct objc_abi_selector *_Nullable sel_refs;
 	uint16_t cls_def_cnt;
 	uint16_t cat_def_cnt;
-	void *OBJC_NONNULL defs[1];
+	void *_Nonnull defs[1];
 };
 
 struct objc_abi_module {
 	unsigned long version;	/* 9 = non-fragile */
 	unsigned long size;
-	const char *OBJC_NULLABLE name;
-	struct objc_abi_symtab *OBJC_NONNULL symtab;
+	const char *_Nullable name;
+	struct objc_abi_symtab *_Nonnull symtab;
 };
 
 struct objc_hashtable_bucket {
-	const void *OBJC_NONNULL key, *OBJC_NONNULL obj;
+	const void *_Nonnull key, *_Nonnull obj;
 	uint32_t hash;
 };
 
 struct objc_hashtable {
-	uint32_t (*OBJC_NONNULL hash)(const void *OBJC_NONNULL key);
-	bool (*OBJC_NONNULL equal)(const void *OBJC_NONNULL key1,
-	    const void *OBJC_NONNULL key2);
+	uint32_t (*_Nonnull hash)(const void *_Nonnull key);
+	bool (*_Nonnull equal)(const void *_Nonnull key1,
+	    const void *_Nonnull key2);
 	uint32_t count, size;
-	struct objc_hashtable_bucket *OBJC_NONNULL *OBJC_NULLABLE data;
+	struct objc_hashtable_bucket *_Nonnull *_Nullable data;
 };
 
 struct objc_sparsearray {
 	struct objc_sparsearray_data {
-		void *OBJC_NULLABLE next[256];
-	} *OBJC_NONNULL data;
+		void *_Nullable next[256];
+	} *_Nonnull data;
 	uint8_t index_size;
 };
 
 struct objc_dtable {
 	struct objc_dtable_level2 {
 #ifdef OF_SELUID24
 		struct objc_dtable_level3 {
-			IMP OBJC_NULLABLE buckets[256];
-		} *OBJC_NONNULL buckets[256];
+			IMP _Nullable buckets[256];
+		} *_Nonnull buckets[256];
 #else
-		IMP OBJC_NULLABLE buckets[256];
+		IMP _Nullable buckets[256];
 #endif
-	} *OBJC_NONNULL buckets[256];
+	} *_Nonnull buckets[256];
 };
 
-extern void objc_register_all_categories(struct objc_abi_symtab *OBJC_NONNULL);
-extern struct objc_category *OBJC_NULLABLE *OBJC_NULLABLE
-    objc_categories_for_class(Class OBJC_NONNULL);
+extern void objc_register_all_categories(struct objc_abi_symtab *_Nonnull);
+extern struct objc_category *_Nullable *_Nullable
+    objc_categories_for_class(Class _Nonnull);
 extern void objc_unregister_all_categories(void);
-extern void objc_initialize_class(Class OBJC_NONNULL);
-extern void objc_update_dtable(Class OBJC_NONNULL);
-extern void objc_register_all_classes(struct objc_abi_symtab *OBJC_NONNULL);
-extern Class OBJC_NULLABLE objc_classname_to_class(const char *OBJC_NONNULL,
-    bool);
-extern void objc_unregister_class(Class OBJC_NONNULL);
+extern void objc_initialize_class(Class _Nonnull);
+extern void objc_update_dtable(Class _Nonnull);
+extern void objc_register_all_classes(struct objc_abi_symtab *_Nonnull);
+extern Class _Nullable objc_classname_to_class(const char *_Nonnull, bool);
+extern void objc_unregister_class(Class _Nonnull);
 extern void objc_unregister_all_classes(void);
-extern uint32_t objc_hash_string(const void *OBJC_NONNULL);
-extern bool objc_equal_string(const void *OBJC_NONNULL,
-    const void *OBJC_NONNULL);
-extern struct objc_hashtable *OBJC_NONNULL objc_hashtable_new(
-    uint32_t (*OBJC_NONNULL)(const void *OBJC_NONNULL),
-    bool (*OBJC_NONNULL)(const void *OBJC_NONNULL, const void *OBJC_NONNULL),
-    uint32_t);
+extern uint32_t objc_hash_string(const void *_Nonnull);
+extern bool objc_equal_string(const void *_Nonnull, const void *_Nonnull);
+extern struct objc_hashtable *_Nonnull objc_hashtable_new(
+    uint32_t (*_Nonnull)(const void *_Nonnull),
+    bool (*_Nonnull)(const void *_Nonnull, const void *_Nonnull), uint32_t);
 extern struct objc_hashtable_bucket objc_deleted_bucket;
-extern void objc_hashtable_set(struct objc_hashtable *OBJC_NONNULL,
-    const void *OBJC_NONNULL, const void *OBJC_NONNULL);
-extern void *OBJC_NULLABLE objc_hashtable_get(
-    struct objc_hashtable *OBJC_NONNULL, const void *OBJC_NONNULL);
-extern void objc_hashtable_delete(struct objc_hashtable *OBJC_NONNULL,
-    const void *OBJC_NONNULL);
-extern void objc_hashtable_free(struct objc_hashtable *OBJC_NONNULL);
-extern void objc_register_selector(struct objc_abi_selector *OBJC_NONNULL);
-extern void objc_register_all_selectors(struct objc_abi_symtab *OBJC_NONNULL);
+extern void objc_hashtable_set(struct objc_hashtable *_Nonnull,
+    const void *_Nonnull, const void *_Nonnull);
+extern void *_Nullable objc_hashtable_get(struct objc_hashtable *_Nonnull,
+    const void *_Nonnull);
+extern void objc_hashtable_delete(struct objc_hashtable *_Nonnull,
+    const void *_Nonnull);
+extern void objc_hashtable_free(struct objc_hashtable *_Nonnull);
+extern void objc_register_selector(struct objc_abi_selector *_Nonnull);
+extern void objc_register_all_selectors(struct objc_abi_symtab *_Nonnull);
 extern void objc_unregister_all_selectors(void);
-extern struct objc_sparsearray *OBJC_NONNULL objc_sparsearray_new(uint8_t);
-extern void *OBJC_NULLABLE objc_sparsearray_get(
-    struct objc_sparsearray *OBJC_NONNULL, uintptr_t);
-extern void objc_sparsearray_set(struct objc_sparsearray *OBJC_NONNULL,
-    uintptr_t, void *OBJC_NULLABLE);
-extern void objc_sparsearray_free(struct objc_sparsearray *OBJC_NONNULL);
-extern struct objc_dtable *OBJC_NONNULL objc_dtable_new(void);
-extern void objc_dtable_copy(struct objc_dtable *OBJC_NONNULL,
-    struct objc_dtable *OBJC_NONNULL);
-extern void objc_dtable_set(struct objc_dtable *OBJC_NONNULL, uint32_t,
-    IMP OBJC_NULLABLE);
-extern void objc_dtable_free(struct objc_dtable *OBJC_NONNULL);
+extern struct objc_sparsearray *_Nonnull objc_sparsearray_new(uint8_t);
+extern void *_Nullable objc_sparsearray_get(struct objc_sparsearray *_Nonnull,
+    uintptr_t);
+extern void objc_sparsearray_set(struct objc_sparsearray *_Nonnull, uintptr_t,
+    void *_Nullable);
+extern void objc_sparsearray_free(struct objc_sparsearray *_Nonnull);
+extern struct objc_dtable *_Nonnull objc_dtable_new(void);
+extern void objc_dtable_copy(struct objc_dtable *_Nonnull,
+    struct objc_dtable *_Nonnull);
+extern void objc_dtable_set(struct objc_dtable *_Nonnull, uint32_t,
+    IMP _Nullable);
+extern void objc_dtable_free(struct objc_dtable *_Nonnull);
 extern void objc_dtable_cleanup(void);
-extern void objc_init_static_instances(struct objc_abi_symtab *OBJC_NONNULL);
+extern void objc_init_static_instances(struct objc_abi_symtab *_Nonnull);
 extern void objc_forget_pending_static_instances(void);
 #ifdef OF_HAVE_THREADS
 extern void objc_global_mutex_lock(void);
 extern void objc_global_mutex_unlock(void);
 extern void objc_global_mutex_free(void);
@@ -183,16 +181,16 @@
 # define objc_global_mutex_lock()
 # define objc_global_mutex_unlock()
 # define objc_global_mutex_free()
 #endif
 
-static inline IMP OBJC_NULLABLE
-objc_dtable_get(const struct objc_dtable *OBJC_NONNULL dtable, uint32_t idx)
+static inline IMP _Nullable
+objc_dtable_get(const struct objc_dtable *_Nonnull dtable, uint32_t idx)
 {
 #ifdef OF_SELUID24
 	uint8_t i = idx >> 16;
-	uint8_t j = idx >>  8;
+	uint8_t j = idx >> 8;
 	uint8_t k = idx;
 
 	return dtable->buckets[i]->buckets[j]->buckets[k];
 #else
 	uint8_t i = idx >> 8;
@@ -224,8 +222,5 @@
 		fprintf(stderr, "[objc @ " __FILE__ ":%d] ", __LINE__);	\
 		fprintf(stderr, __VA_ARGS__);				\
 		fputs("\n", stderr);					\
 		abort();						\
 	}
-
-#undef OBJC_NONNULL
-#undef OBJC_NULLABLE