diff --git a/configure.ac b/configure.ac
index 088a0a99..7acc3352 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,7 +50,7 @@ AC_CHECK_FUNCS(arc4random_buf futimes \
 	getutent initgroups lckpwdf lutimes \
 	setgroups updwtmp updwtmpx innetgr \
 	getspnam_r \
-	memset_s explicit_bzero)
+	memset_explicit explicit_bzero)
 AC_SYS_LARGEFILE
 
 dnl Checks for typedefs, structures, and compiler characteristics.
diff --git a/lib/defines.h b/lib/defines.h
index 1a25e580..54053103 100644
--- a/lib/defines.h
+++ b/lib/defines.h
@@ -47,8 +47,8 @@
 #include <sys/time.h>
 #include <time.h>
 
-#ifdef HAVE_MEMSET_S
-# define memzero(ptr, size) memset_s((ptr), 0, (size))
+#ifdef HAVE_MEMSET_EXPLICIT
+# define memzero(ptr, size) memset_explicit((ptr), 0, (size))
 #elif defined HAVE_EXPLICIT_BZERO	/* !HAVE_MEMSET_S */
 # define memzero(ptr, size) explicit_bzero((ptr), (size))
 #else					/* !HAVE_MEMSET_S && HAVE_EXPLICIT_BZERO */