[gmime] Updated PORTING

[Jeffrey Stedfast <fejj src gnome org>]

commit 3547e05d5faa87fcc7794f4feec328c24c030495
Author: Jeffrey Stedfast <jestedfa microsoft com>
Date:   Tue Feb 7 13:42:39 2017 -0500

    Updated PORTING

 PORTING |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/PORTING b/PORTING
index 843a6d7..d12f065 100644
--- a/PORTING
+++ b/PORTING
@@ -34,6 +34,15 @@ Porting from GMime 2.6 to GMime 3.0
   due to the fact that it can now be used to add mailbox addresses to the
   Sender, From, and Reply-To headers as well.
 
+- g_mime_message_set_subject() now takes a charset argument used when encoding
+  the subject into rfc2047 encoded-word tokens (if needed). Use `NULL` to
+  get the old behavior of using a best-fit charset.
+
+- g_mime_set_user_charsets() and g_mime_user_charsets() have been removed.
+  All encoding API's now have a way to specify a charset to use and all
+  decoder API's take a GMimeParserOptions argument that allows for
+  specifying fallback charsets.
+
 - GMimeObject's prepend_header(), append_header(), and set_header() virtual
   methods now all take a const char *raw_value and gint64 offset arguments.
   The raw_value is the raw header value cloned exactly as the parser found
@@ -67,6 +76,9 @@ Porting from GMime 2.6 to GMime 3.0
 
 - Removed g_mime_gpg_context_[get,set]_use_agent(). This should no longer be needed.
 
+- GMimeSignatureStatus and GMimeSignatureErrors have been merged into a
+  single bitfield (GMimeSignatureStatus) which mirrors gpgme_sigsum_t.
+
 
 Porting from GMime 2.4 to GMime 2.6
 -----------------------------------