diff --git a/include/m_string.h b/include/m_string.h
index c3dcf19e73d..2e443a87736 100644
--- a/include/m_string.h
+++ b/include/m_string.h
@@ -61,6 +61,10 @@
 # define bfill(A,B,C)           memset((A),(C),(B))
 #endif
 
+#if !defined(bzero) && !defined(HAVE_BZERO)
+# define bzero(A,B)             memset((A),0,(B))
+#endif
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
@@ -104,10 +108,6 @@ extern char NEAR _dig_vec_lower[];
 extern	void bfill(uchar *dst,size_t len,pchar fill);
 #endif
 
-#if !defined(bzero) && !defined(HAVE_BZERO)
-extern	void bzero(uchar * dst,size_t len);
-#endif
-
 #ifndef bmove512
 extern	void bmove512(uchar *dst,const uchar *src,size_t len);
 #endif