Index: src/macros.h
==================================================================
--- src/macros.h
+++ src/macros.h
@@ -98,11 +98,11 @@
 #else
 # define OF_PATH_DELIMITER '\\'
 #endif
 
 extern id objc_getProperty(id, SEL, ptrdiff_t, BOOL);
-extern void objc_setProperty(id, SEL, ptrdiff_t, id, BOOL, BOOL);
+extern void objc_setProperty(id, SEL, ptrdiff_t, id, BOOL, signed char);
 
 #define OF_IVAR_OFFSET(ivar) ((intptr_t)&ivar - (intptr_t)self)
 #define OF_GETTER(ivar, atomic) \
 	return objc_getProperty(self, _cmd, OF_IVAR_OFFSET(ivar), atomic);
 #define OF_SETTER(ivar, value, atomic, copy) \

Index: src/objc_properties.m
==================================================================
--- src/objc_properties.m
+++ src/objc_properties.m
@@ -64,11 +64,11 @@
 	return *(id*)(void*)((char*)self + offset);
 }
 
 void
 objc_setProperty(id self, SEL _cmd, ptrdiff_t offset, id value, BOOL atomic,
-    BOOL copy)
+    signed char copy)
 {
 	if (atomic) {
 		id *ptr = (id*)(void*)((char*)self + offset);
 #ifdef OF_THREADS
 		unsigned hash = SPINLOCK_HASH(ptr);
@@ -82,15 +82,10 @@
 			switch (copy) {
 			case 0:
 				*ptr = [value retain];
 				break;
 			case 2:
-				/*
-				 * Apple uses this to indicate that the copy
-				 * should be mutable. Please hit them for
-				 * abusing a poor BOOL!
-				 */
 				*ptr = [value mutableCopy];
 				break;
 			default:
 				*ptr = [value copy];
 			}