Fix a few compiler warnings.  Fix crash with encrypted undo file.
diff --git a/src/feature.h b/src/feature.h
index 5bca7c7..7a38b85 100644
--- a/src/feature.h
+++ b/src/feature.h
@@ -127,7 +127,7 @@
 #endif
 
 /*
- * Message history is fixed at 100 message, 20 for the tiny version.
+ * Message history is fixed at 200 message, 20 for the tiny version.
  */
 #ifdef FEAT_SMALL
 # define MAX_MSG_HIST_LEN 200