[libxml2] Add TODO comment in xmlSwitchEncoding

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 45ce1ee3994b73e30b8e2bda9dbfbb99e5347b66
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Jun 9 15:27:25 2017 +0200

    Add TODO comment in xmlSwitchEncoding
    
    It would be nice if we could recover from unsupported encodings in
    external entities.

 parserInternals.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/parserInternals.c b/parserInternals.c
index b867cbc..67e5518 100644
--- a/parserInternals.c
+++ b/parserInternals.c
@@ -1101,6 +1101,11 @@ xmlSwitchEncoding(xmlParserCtxtPtr ctxt, xmlCharEncoding enc)
                break;
        }
     }
+    /*
+     * TODO: We could recover from errors in external entites if we
+     * didn't stop the parser. But most callers of this function don't
+     * check the return value.
+     */
     if (handler == NULL) {
         xmlStopParser(ctxt);
        return(-1);