diff --git a/Zend/zend_portability.h b/Zend/zend_portability.h
index f4609428326c7..5acbebf30ff96 100644
--- a/Zend/zend_portability.h
+++ b/Zend/zend_portability.h
@@ -47,6 +47,11 @@
 #include "../TSRM/TSRM.h"
 
 #include <stdio.h>
+#if ZEND_DEBUG
+# undef NDEBUG
+#elif !defined(NDEBUG)
+# define NDEBUG
+#endif
 #include <assert.h>
 #include <math.h>
 
diff --git a/main/php.h b/main/php.h
index c00777a1b40a0..a7ff4b6e35bea 100644
--- a/main/php.h
+++ b/main/php.h
@@ -109,13 +109,6 @@ typedef int pid_t;
 # endif
 #endif
 
-#if PHP_DEBUG
-#undef NDEBUG
-#else
-#ifndef NDEBUG
-#define NDEBUG
-#endif
-#endif
 #include <assert.h>
 
 #ifdef HAVE_UNIX_H