py: Allow to compile with extra warnings (sign-compare, unused-param).
diff --git a/py/objstrunicode.c b/py/objstrunicode.c
index abef234..1cf4ed4 100644
--- a/py/objstrunicode.c
+++ b/py/objstrunicode.c
@@ -53,7 +53,7 @@
             has_double_quote = true;
         }
     }
-    int quote_char = '\'';
+    unichar quote_char = '\'';
     if (has_single_quote && !has_double_quote) {
         quote_char = '"';
     }