mail: Remove Content-Disposition headers

The Content-Disposition headers quilt has been adding since 2015 are
causing problems with Thunderbird and Gmail, which display patches as
attachments instead of text if this header is present and includes a
filename.  This breaks email-based patch reviewing and isn't likely to
get fixed on the email client side, so stop adding those headers.

Recipients of patches via email already need a mechanism to construct
filenames for messages coming from anything but quilt, so this change is
unlikely to cause major problems for existing users.

2 files changed, 3 insertions, 6 deletions

diff --git a/doc/README.MAIL b/doc/README.MAIL
index c997048..f1403dd 100644
--- a/doc/README.MAIL
+++ b/doc/README.MAIL
@@ -19,11 +19,9 @@ that @total@ has.
 
 Each message is assigned a unique Message-Id header, and all messages
 other than the introduction are made to refer to the introduction (using
-a References header) for proper message threading in mail clients.
-Patch filenames are stored in Content-Disposition headers so that mail
-clients will know the original filename.  The message timestamps in Date
-headers in each message is incremented by one second per message, starting
-with the timestamp of the introduction.
+a References header) for proper message threading in mail clients.  The
+message timestamps in Date headers in each message is incremented by one
+second per message, starting with the timestamp of the introduction.
 
 If a ~/.signature file exists, this file is appended to each message
 generated.
diff --git a/quilt/mail.in b/quilt/mail.in
index 91cd3b6..91d667f 100644
--- a/quilt/mail.in
+++ b/quilt/mail.in
@@ -637,7 +637,6 @@ for patch in "${patches[@]}"; do
 		references_header $introduction
 		echo "MIME-Version: 1.0"
 		echo "Content-Type: text/plain; charset=$opt_charset"
-		echo "Content-Disposition: inline; filename=$patch"
 		awk '
 		    kill_header { if (/^[ \t]/) next ; kill_header = 0 }
 		    !in_body && tolower($0) ~ /^(recipient|replace)-.*:/ \