diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 4d13611..69a0c88 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -33,6 +33,10 @@
 #include <signal.h>
 #include <setjmp.h>
 
+#ifdef macintosh
+#define NO_UNISTD
+#endif
+
 #ifndef NO_UNISTD
 #include <unistd.h>
 #endif
diff --git a/Objects/classobject.c b/Objects/classobject.c
index 8164ced..d4a2f82 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -396,7 +396,7 @@
 		arg = mkvalue("(OO)", key, value);
 	if (arg == NULL) {
 		DECREF(func);
-		return NULL;
+		return -1;
 	}
 	res = call_object(func, arg);
 	DECREF(func);
@@ -509,14 +509,14 @@
 	else
 		func = instance_getattr(inst, "__setitem__");
 	if (func == NULL)
-		return NULL;
+		return -1;
 	if (item == NULL)
 		arg = mkvalue("i", i);
 	else
 		arg = mkvalue("(iO)", i, item);
 	if (arg == NULL) {
 		DECREF(func);
-		return NULL;
+		return -1;
 	}
 	res = call_object(func, arg);
 	DECREF(func);
@@ -540,14 +540,14 @@
 	else
 		func = instance_getattr(inst, "__setslice__");
 	if (func == NULL)
-		return NULL;
+		return -1;
 	if (value == NULL)
 		arg = mkvalue("(ii)", i, j);
 	else
 		arg = mkvalue("(iiO)", i, j, value);
 	if (arg == NULL) {
 		DECREF(func);
-		return NULL;
+		return -1;
 	}
 	res = call_object(func, arg);
 	DECREF(func);