From c633dca1ee76f0caf9183879d82ec46c3c37064f Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Mon, 4 May 2015 11:01:14 +0100
Subject: [PATCH] local.m4: Rename headers with special significance to
 Dovecot.

---
 local.m4 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/local.m4 b/local.m4
index f3b5e9f..582e1ce 100644
--- a/local.m4
+++ b/local.m4
@@ -101,11 +101,20 @@ FILTER_ROUTER(dot_forward,
 
 SECTION(routers, deliver)m4_dnl
 ## Deliver mail to a user, in the absence of any other instructions.
+m4_define(<:STRIP_HEADERS:>, <:m4_dnl
+	Content-Length, Status, X-IMAP, X-IMAPbase, m4_dnl
+	X-Keywords, X-Status, X-UID:>)m4_dnl
 deliver:
 	driver = accept
 	check_local_user
 	transport = deliver
 	cannot_route_message = Unknown local part
 
+	## Strip headers used by Dovecot for its own purposes.
+	headers_remove = CLRSEP<::>FOREACH(<:SEP(:)$1:>, <:STRIP_HEADERS:>)
+	headers_add = CLRSEP<::>FOREACH(<:\
+		${if def:h_$1:{X-Distorted-Renamed-$1: $h_$1:\n}}:>,
+		<:STRIP_HEADERS:>)
+
 DIVERT(null)
 ###----- That's all, folks --------------------------------------------------
-- 
2.11.0