Signed-off-by: Olaf Hering <olaf@aepfle.de>

This is just an initial version, complete with typos and other
mistakes. Committing now so translators can refer to it.

Include attachments if it is 'yes' or 'ask-yes', like $copy and
$send_multipart_alternative.

Emulate the behavior of $copy, which performs fcc for 'yes' or
'ask-yes' values.

add view-alt function, so now we have
* view-alt "v"
* view-alt-text "Esc v"
* view-alt-mailcap "V"

Changing to mutt_read_line() avoids -Wunused-result warning while
reading the ignored line in query protocol response.

Most of these were already commented. Change a few of them to
a format gcc will recognize. In the future, we'll want to change to
whatever is standardized.

Some mail clients (*cough* Apple Mail) have started to put email
attachments in one of the multipart/alternative branches.

The config changes the searching to recurse inside alternatives when
performing attachment counting.

_() can invoke malloc, so remove l10n translations.

printf() is not safe either, so use write().

I'm not sure at this point about curs_set() and endwin(), but they
seem important enough for proper terminal cleanup to risk leaving in.

Thanks to Oswald Buddenhagen for pointing out the problem, and the old
trac ticket from Vincent at:
<https://gitlab.com/muttmua/trac-tickets/raw/master/tickets/open/3791-SIGQUIT_Ctrl_while_opening_mailbox_made_Mutt_hang.txt>

This was contributed by martin f. kraft, to give an example script for
the new $send_multipart_alternative_filter funtionality.

I recall seeing a message on IRC, where someone reported their macro
suddenly aborting after invoking an editor or something similar. At
the time, I wasn't sure of the problem, but this seems a likely
culprit, if the event caused a sigwinch.

Neither the menu.c nor the pager.c SigWinch handlers do such a thing.
The line was part of the initial import 21 years ago, so there is no
justification given.

Reset the SigWinch flag before the screen resize/reflow, not afterwards.

Change Fcc'ing to always write a Bcc header regardless of the setting.

Update the variable documentation to note the difference when Fcc'ing.

Since generating multipart types using
$send_multipart_alternative_filter will not send properly, display an
error message and block alternatives of that type.

There was no code that explicitly enabled APP_PGP mode when either the
recommendation engine or autocrypt menu were invoked. This would
cause the actual encryption to fail when sending.

This was hidden by the $crypt_opportunistic_encrypt config, which does
ensure it gets turned on. I can only guess that this variable is
popular with the autocrypt early adopters too.

Also explicity enable APP_PGP for $autocrypt_reply. We can't rely on
$crypt_autopgp to turn this on.

Create config variables $send_multipart_alternative (a quadoption)
and $send_multipart_alternative_filter. The filter script expects
output to be the mime type, a blank line, then the content.

Add ability to preview alternative from compose menu. <view-alt-text>
forces viewing as text. <view-alt-mailcap> forces using the mailcap.
Bind them to 'v' and 'V', respectively.

Improve <resend-message> so a multipart/alternative is stripped out,
which would just confuse the compose menu. Currently this preserves
the first alternative.

Allow alternative generation in batch mode, as long as the quadoption
is set to 'yes'.

Since we will be dealing with multipart/alternative, we need the
helpers to be a bit more specific.

We need to distinguish a top-level multipart/alternative from a
multipart/mixed created because of attachments.

MS Outlook seems to add charset=charset=utf-8 to Content-Type, which
results in charset_utf-8 inside Mutt, which in turn confuses others.

Strip a leading charset= from charset, so we work around this odd
behaviour.

Signed-off-by: Fabian Groffen <grobian@gentoo.org>

Because of the mutt_body_handler() invocation, we avoid using the
buffer pool.

Clean up the error handling a bit.

Because of the recursive invocation, avoid the buffer pool in this
case.

This affects the send.c flow (ci_send_message()), the compose menu,
and various helper functions.

Because of mime_lookup commands, the call to mutt_check_lookup_list()
inside the function can modify the passed in type. Add an explicit
length parameter to the function, rather than assume the parameter
size. This also makes it more evident the type parameter can be
modified to callers.

Change the len parameter to mutt_check_lookup_list() to type size_t,
just to be correct about it.

Adjust the rfc1524_mailcap_parse() and get_field_text() filename and
type parameters to be const.

Note that the sizeof(type) needs to be passed to
rfc1524_mailcap_lookup(). I'll fix that next.