diff --git a/Headers/gnustep/base/NSZone.h b/Headers/gnustep/base/NSZone.h
index f49f00f04..7ac75614f 100644
--- a/Headers/gnustep/base/NSZone.h
+++ b/Headers/gnustep/base/NSZone.h
@@ -25,7 +25,7 @@
 #ifndef h_zone_NS_h
 #define h_zone_NS_h
 
-#ifdef __NeXT__
+#if NeXT_runtime
 #import <objc/zone.h>
 #define NSZone NXZone
 #else
diff --git a/Source/NSZone.c b/Source/NSZone.c
index 8e18a5bc8..3b51b7eca 100644
--- a/Source/NSZone.c
+++ b/Source/NSZone.c
@@ -73,7 +73,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <malloc.h>
+#ifndef __NeXT__
+# include <malloc.h>
+#endif
 #include <Foundation/NSZone.h>
 #include <objects/objc-malloc.h>