[gimp] app: output an error message when iso code parsing failed.

[Jehan Pagès <jehanp src gnome org>]

commit e23ee850d5d53d400aa54c5d84352eb900ade89b
Author: Jehan <jehan girinstud io>
Date:   Mon Jun 12 01:17:17 2017 +0200

    app: output an error message when iso code parsing failed.
    
    Thanks to Lionel N. who bugged me with his Windows installation where
    the XML file was not found by GIMP. We should output a warning when this
    happens so that packagers can detect the issue and the expected
    installation path for this dependency.
    The reporter wants me to call him "Padawan Lionel" but I won't fall for
    it! Or did I? :-D

 app/widgets/gimplanguagestore-parser.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/app/widgets/gimplanguagestore-parser.c b/app/widgets/gimplanguagestore-parser.c
index da49e97..96574bf 100644
--- a/app/widgets/gimplanguagestore-parser.c
+++ b/app/widgets/gimplanguagestore-parser.c
@@ -97,6 +97,7 @@ gimp_language_store_parser_init (void)
   GHashTable     *base_lang_list;
   gchar          *current_env;
   GDir           *locales_dir;
+  GError         *error = NULL;
   GHashTableIter  lang_iter;
   gpointer        key;
 
@@ -165,7 +166,7 @@ gimp_language_store_parser_init (void)
     }
 
   /* Parse ISO-639 file to get full list of language and their names. */
-  parse_iso_codes (base_lang_list, NULL);
+  parse_iso_codes (base_lang_list, &error);
 
   /* Generate the localized language names. */
   g_hash_table_iter_init (&lang_iter, l10n_lang_list);
@@ -343,6 +344,13 @@ parse_iso_codes (GHashTable  *base_lang_list,
 #endif
 
   success = gimp_xml_parser_parse_gfile (xml_parser, file, error);
+  if (error && *error)
+    {
+      g_warning ("%s: error parsing '%s': %s\n",
+                 G_STRFUNC, g_file_get_path (file),
+                 (*error)->message);
+      g_clear_error (error);
+    }
 
   g_object_unref (file);