[geary] Always use UTF-8 for encoding non-ASCII/ISO-8859-1 headers. Bug 753870.

[Michael Gratton <mjog src gnome org>]

commit f10f898ab0c9dfeaeac82a5f969dbc8e0d3512c3
Author: Michael James Gratton <mike vee net>
Date:   Thu Jun 30 15:29:39 2016 +1000

    Always use UTF-8 for encoding non-ASCII/ISO-8859-1 headers. Bug 753870.
    
    While message bodies are always sent as UTF-8, non ASCII/ISO-8859-1
    headers were being encoded using GMime's default heuristics. This
    uses some less-well-supported charsets and causing some rendering
    issues in other less tolerant client.
    
    Since we assume UTF-8 support for the body, assume it for headers as
    well.
    
    * src/engine/rfc822/rfc822.vala (Geary.RFC822.init): Set GMime user
      charsets to UTF-8.
    
    * bindings/vapi/gmime-2.6.vapi (GMime): Fix binding for
      g_mime_set_user_charsets.

 bindings/vapi/gmime-2.6.vapi  |    2 +-
 src/engine/rfc822/rfc822.vala |   10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/bindings/vapi/gmime-2.6.vapi b/bindings/vapi/gmime-2.6.vapi
index 59c6909..0bb1991 100644
--- a/bindings/vapi/gmime-2.6.vapi
+++ b/bindings/vapi/gmime-2.6.vapi
@@ -1342,7 +1342,7 @@ namespace GMime {
        [CCode (cheader_filename = "gmime/gmime.h", cname = "g_mime_locale_language")]
        public static unowned string locale_language ();
        [CCode (cheader_filename = "gmime/gmime.h", cname = "g_mime_set_user_charsets")]
-       public static void set_user_charsets (out unowned string charsets);
+       public static void set_user_charsets ([CCode (array_length = false)] string[] charsets);
        [CCode (cheader_filename = "gmime/gmime.h", cname = "g_mime_shutdown")]
        public static void shutdown ();
        [CCode (cheader_filename = "gmime/gmime.h", cname = "g_mime_user_charsets")]
diff --git a/src/engine/rfc822/rfc822.vala b/src/engine/rfc822/rfc822.vala
index f625671..b09376a 100644
--- a/src/engine/rfc822/rfc822.vala
+++ b/src/engine/rfc822/rfc822.vala
@@ -14,6 +14,11 @@ public enum TextFormat {
     HTML
 }
 
+// This has the effect of ensuring all non US-ASCII and non-ISO-8859-1
+// headers are always encoded as UTF-8. This should be fine because
+// message bodies are also always sent as UTF-8.
+private const string[] USER_CHARSETS =  { "UTF-8" };
+
 private int init_count = 0;
 
 internal Regex? invalid_filename_character_re = null;
@@ -21,9 +26,10 @@ internal Regex? invalid_filename_character_re = null;
 public void init() {
     if (init_count++ != 0)
         return;
-    
+
     GMime.init(GMime.ENABLE_RFC2047_WORKAROUNDS);
-    
+    GMime.set_user_charsets(USER_CHARSETS);
+
     try {
         invalid_filename_character_re = new Regex("[/\\0]");
     } catch (RegexError e) {