diff --git a/src/libsodium/sodium/utils.c b/src/libsodium/sodium/utils.c
index a04bf1b9..85aad292 100644
--- a/src/libsodium/sodium/utils.c
+++ b/src/libsodium/sodium/utils.c
@@ -21,22 +21,24 @@
 # include <unistd.h>
 #endif
 
-#if HAVE_ALLOCA_H
-# include <alloca.h>
-#elif !defined(alloca)
-# if defined(__GNUC__)
-#  define alloca __builtin_alloca
-# elif defined _AIX
-#  define alloca __alloca
-# elif defined _MSC_VER
-#  include <malloc.h>
-#  define alloca _alloca
-# else
-#  include <stddef.h>
-#  ifdef  __cplusplus
+#ifndef HAVE_C_VARARRAYS
+# ifdef HAVE_ALLOCA_H
+#  include <alloca.h>
+# elif !defined(alloca)
+#  if defined(__GNUC__)
+#   define alloca __builtin_alloca
+#  elif defined _AIX
+#   define alloca __alloca
+#  elif defined _MSC_VER
+#   include <malloc.h>
+#   define alloca _alloca
+#  else
+#   include <stddef.h>
+#   ifdef  __cplusplus
 extern "C"
-#  endif
+#   endif
 void *alloca (size_t);
+#  endif
 # endif
 #endif
 
@@ -128,11 +130,11 @@ sodium_memzero(void *const pnt, const size_t len)
 void
 sodium_stackzero(const size_t len)
 {
-#ifdef HAVE_ALLOCA
-    sodium_memzero(alloca(len), len);
-#elif HAVE_C_VARARRAYS
+#ifdef HAVE_C_VARARRAYS
     unsigned char fodder[len];
     sodium_memzero(fodder, len);
+#elif HAVE_ALLOCA
+    sodium_memzero(alloca(len), len);
 #endif
 }