[mutter] xprops: Make sure text_property_to_utf8() returns UTF8

[Jonas Ådahl <jadahl src gnome org>]

commit 76abe87090830b27e2c624b9854ca94829b04a75
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Oct 9 00:29:01 2018 +0200

    xprops: Make sure text_property_to_utf8() returns UTF8
    
    Commit 840378ae682 changed the code to use XmbTextPropertyToTextList()
    instead of gdk_text_property_to_utf8_list_for_display(), but didn't
    take into account that the replacement returns text in the current
    locale's encoding, while any callers (rightfully) expect UTF8.
    
    Fix this by converting the text if necessary.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/227

 src/x11/xprops.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/src/x11/xprops.c b/src/x11/xprops.c
index ae05afe14..2bef29985 100644
--- a/src/x11/xprops.c
+++ b/src/x11/xprops.c
@@ -639,6 +639,7 @@ text_property_to_utf8 (Display *xdisplay,
 {
   char *ret = NULL;
   char **local_list = NULL;
+  const char *charset = NULL;
   int count = 0;
   int res;
 
@@ -649,7 +650,10 @@ text_property_to_utf8 (Display *xdisplay,
   if (count == 0)
     goto out;
 
-  ret = g_strdup (local_list[0]);
+  if (g_get_charset (&charset))
+    ret = g_strdup (local_list[0]);
+  else
+    ret = g_convert (local_list[0], -1, "UTF-8", charset, NULL, NULL, NULL);
 
  out:
   XFreeStringList (local_list);