diff --git a/websockets.scm b/websockets.scm
index 1960482..d0fe95e 100644
--- a/websockets.scm
+++ b/websockets.scm
@@ -191,6 +191,8 @@
   (define-external wsv scheme-pointer payload)
   ((foreign-lambda* void ()
 "
+    int i;
+
     if (wslen > UINT_MAX) { return -1; }
 
     const unsigned char* maskkey2 = wsmaskkey;
@@ -198,14 +200,14 @@
     const unsigned char* __restrict kb = maskkey2;
 
 
-    for (int i = wslen >> 2; i != 0; --i)
+    for (i = wslen >> 2; i != 0; --i)
     {
         *((unsigned int*)wsv) ^= kd;
         wsv += 4;
     }
 
     const int rem = wslen & 3;
-    for (int i = 0; i < rem; ++i)
+    for (i = 0; i < rem; ++i)
     {
         *((unsigned int*)wsv++) ^= kb[i];
     }
@@ -245,19 +247,21 @@
 ;;         (begin
 ;;           ((foreign-lambda* void ()
 ;; "
+;;     int i;
+;;
 ;;     const unsigned char* maskkey2 = wsmaskkey;
 ;;     const unsigned int kd = *(unsigned int*)maskkey2;
 ;;     const unsigned char* __restrict kb = maskkey2;
 
 
-;;     for (int i = wslen >> 2; i != 0; --i)
+;;     for (i = wslen >> 2; i != 0; --i)
 ;;     {
 ;;         *((unsigned int*)wsv) ^= kd;
 ;;         wsv += 4;
 ;;     }
 
 ;;     const int rem = wslen & 3;
-;;     for (int i = 0; i < rem; ++i)
+;;     for (i = 0; i < rem; ++i)
 ;;     {
 ;;         *((unsigned int*)wsv++) ^= kb[i];
 ;;     }
@@ -341,9 +345,11 @@
          (= 1
             ((foreign-lambda* int ()
 "
+    int i;
+
     if (ws_utlen > UINT_MAX) { return -1; }
 
-    for (int i = ws_utlen; i != 0; --i)
+    for (i = ws_utlen; i != 0; --i)
     {
         if (*((unsigned char*)ws_uts++) > 127)
         {