diff --git a/ext/tinyopt/include/tinyopt/tinyopt.h b/ext/tinyopt/include/tinyopt/tinyopt.h
index e9d55c8d96..9cd2bf903b 100644
--- a/ext/tinyopt/include/tinyopt/tinyopt.h
+++ b/ext/tinyopt/include/tinyopt/tinyopt.h
@@ -892,7 +892,7 @@ struct saved_options: private std::vector<std::string> {
         bool quote = false; // true => within single quotes.
         bool escape = false; // true => previous character was backslash.
         while (in) {
-            char c = in.get();
+            int c = in.get();
             if (c==EOF) break;
 
             if (quote) {