Fixes warnings from MSVC
diff --git a/programs/fuzz/common.c b/programs/fuzz/common.c
index a9d3d3b..169b480 100644
--- a/programs/fuzz/common.c
+++ b/programs/fuzz/common.c
@@ -26,7 +26,10 @@
     (void) buf;
 
     //pretends we wrote everything ok
-    return( len );
+    if (len > INT_MAX) {
+        return -1;
+    }
+    return int( len );
 }
 
 int fuzz_recv( void *ctx, unsigned char *buf, size_t len )