emacs: use lexical-bindings in all libraries

Doing so causes many new compile warnings.  Some of these warnings
concern genuine changes in behavior that have to be addressed right
away.

Many other warnings are due to unused variables.  Nothing has changed
here, except that the byte-compiler can now detect these pre-existing
and harmless issues.  We delay addressing these issues so that we can
focus on the important ones here.

A third group of warnings concern arguments that are not actually used
inside the function but which cannot be removed because the functions
signature is dictated by some outside convention.  Silencing these
warning is also delayed until subsequent commits.

emacs/coolj.el

@@ -1,4 +1,4 @@
-;;; coolj.el --- automatically wrap long lines  -*- coding:utf-8 -*-
+;;; coolj.el --- automatically wrap long lines  -*- lexical-binding: t; coding: utf-8 -*-
 
 ;; Copyright (C) 2000, 2001, 2004-2009 Free Software Foundation, Inc.
 

emacs/make-deps.el

@@ -1,4 +1,4 @@
-;;; make-deps.el --- compute make dependencies for Elisp sources
+;;; make-deps.el --- compute make dependencies for Elisp sources  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Austin Clements
 ;;

emacs/notmuch-address.el

@@ -1,4 +1,4 @@
-;;; notmuch-address.el --- address completion with notmuch
+;;; notmuch-address.el --- address completion with notmuch  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © David Edmondson
 ;;

emacs/notmuch-compat.el

@@ -1,4 +1,4 @@
-;;; notmuch-compat.el --- compatibility functions for earlier versions of emacs
+;;; notmuch-compat.el --- compatibility functions for earlier versions of emacs  -*- lexical-binding: t -*-
 ;;
 ;; The functions in this file are copied from more modern versions of
 ;; emacs and are Copyright (C) 1985-1986, 1992, 1994-1995, 1999-2017

emacs/notmuch-crypto.el

@@ -1,4 +1,4 @@
-;;; notmuch-crypto.el --- functions for handling display of cryptographic metadata
+;;; notmuch-crypto.el --- functions for handling display of cryptographic metadata  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Jameson Rollins
 ;;

emacs/notmuch-draft.el

@@ -1,4 +1,4 @@
-;;; notmuch-draft.el --- functions for postponing and editing drafts
+;;; notmuch-draft.el --- functions for postponing and editing drafts  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Mark Walters
 ;; Copyright © David Bremner

emacs/notmuch-hello.el

@@ -1,4 +1,4 @@
-;;; notmuch-hello.el --- welcome to notmuch, a frontend
+;;; notmuch-hello.el --- welcome to notmuch, a frontend  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © David Edmondson
 ;;

emacs/notmuch-jump.el

@@ -1,4 +1,4 @@
-;;; notmuch-jump.el --- User-friendly shortcut keys
+;;; notmuch-jump.el --- User-friendly shortcut keys  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Austin Clements
 ;;

emacs/notmuch-lib.el

@@ -1,4 +1,4 @@
-;;; notmuch-lib.el --- common variables, functions and function declarations
+;;; notmuch-lib.el --- common variables, functions and function declarations  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Carl Worth
 ;;

emacs/notmuch-maildir-fcc.el

@@ -1,4 +1,4 @@
-;;; notmuch-maildir-fcc.el --- inserting using a fcc handler
+;;; notmuch-maildir-fcc.el --- inserting using a fcc handler  -*- lexical-binding: t -*-
 
 ;; Copyright © Jesse Rosenthal
 ;;

emacs/notmuch-message.el

@@ -1,4 +1,4 @@
-;;; notmuch-message.el --- message-mode functions specific to notmuch
+;;; notmuch-message.el --- message-mode functions specific to notmuch  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Jesse Rosenthal
 ;;

emacs/notmuch-mua.el

@@ -1,4 +1,4 @@
-;;; notmuch-mua.el --- emacs style mail-user-agent
+;;; notmuch-mua.el --- emacs style mail-user-agent  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © David Edmondson
 ;;
@@ -38,6 +38,11 @@
 (declare-function notmuch-draft-postpone "notmuch-draft" ())
 (declare-function notmuch-draft-save "notmuch-draft" ())
 
+(defvar notmuch-show-indent-multipart)
+(defvar notmuch-show-insert-header-p-function)
+(defvar notmuch-show-max-text-part-size)
+(defvar notmuch-show-insert-text/plain-hook)
+
 ;;; Options
 
 (defcustom notmuch-mua-send-hook nil

emacs/notmuch-parser.el

@@ -1,4 +1,4 @@
-;;; notmuch-parser.el --- streaming S-expression parser
+;;; notmuch-parser.el --- streaming S-expression parser  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Austin Clements
 ;;

emacs/notmuch-print.el

@@ -1,4 +1,4 @@
-;;; notmuch-print.el --- printing messages from notmuch
+;;; notmuch-print.el --- printing messages from notmuch  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © David Edmondson
 ;;

emacs/notmuch-query.el

@@ -1,4 +1,4 @@
-;;; notmuch-query.el --- provide an emacs api to query notmuch
+;;; notmuch-query.el --- provide an emacs api to query notmuch  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © David Bremner
 ;;

emacs/notmuch-show.el

@@ -1,4 +1,4 @@
-;;; notmuch-show.el --- displaying notmuch forests
+;;; notmuch-show.el --- displaying notmuch forests  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Carl Worth
 ;; Copyright © David Edmondson
@@ -59,6 +59,10 @@
 (declare-function notmuch-read-query "notmuch" (prompt))
 (declare-function notmuch-draft-resume "notmuch-draft" (id))
 
+(defvar shr-blocked-images)
+(defvar gnus-blocked-images)
+(defvar shr-content-function)
+
 ;;; Options
 
 (defcustom notmuch-message-headers '("Subject" "To" "Cc" "Date")

emacs/notmuch-tag.el

@@ -1,4 +1,4 @@
-;;; notmuch-tag.el --- tag messages within emacs
+;;; notmuch-tag.el --- tag messages within emacs  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Damien Cassou
 ;; Copyright © Carl Worth
@@ -295,22 +295,24 @@ This can be used with `notmuch-tag-format-image-data'."
 		      (and (eq (string-match key tag) 0)
 			   (= (match-end 0) (length tag)))))))
 
-(defun notmuch-tag--do-format (tag formatted-tag formats)
+(defun notmuch-tag--do-format (bare-tag tag formats)
   "Apply a tag-formats entry to TAG."
   (cond ((null formats)		;; - Tag not in `formats',
-	 formatted-tag)	       	;;   the format is the tag itself.
+	 tag)			;;   the format is the tag itself.
 	((null (cdr formats))	;; - Tag was deliberately hidden,
 	 nil)			;;   no format must be returned
 	(t
 	 ;; Tag was found and has formats, we must apply all the
 	 ;; formats.  TAG may be null so treat that as a special case.
-	 (let ((bare-tag tag)
+	 (let ((return-tag (copy-sequence (or tag ""))))
-	       (tag (copy-sequence (or formatted-tag ""))))
 	   (dolist (format (cdr formats))
-	     (setq tag (eval format)))
+	     (setq return-tag
-	   (if (and (null formatted-tag) (equal tag ""))
+		   (eval format
+			 `((bare-tag . ,bare-tag)
+			   (tag . ,return-tag)))))
+	   (if (and (null tag) (equal return-tag ""))
 	       nil
-	     tag)))))
+	     return-tag)))))
 
 (defun notmuch-tag-format-tag (tags orig-tags tag)
   "Format TAG according to `notmuch-tag-formats'.

emacs/notmuch-tree.el

@@ -1,4 +1,4 @@
-;;; notmuch-tree.el --- displaying notmuch forests
+;;; notmuch-tree.el --- displaying notmuch forests  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Carl Worth
 ;; Copyright © David Edmondson

emacs/notmuch-wash.el

@@ -1,4 +1,4 @@
-;;; notmuch-wash.el --- cleaning up message bodies
+;;; notmuch-wash.el --- cleaning up message bodies  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Carl Worth
 ;; Copyright © David Edmondson

emacs/notmuch.el

@@ -1,4 +1,4 @@
-;;; notmuch.el --- run notmuch within emacs
+;;; notmuch.el --- run notmuch within emacs  -*- lexical-binding: t -*-
 ;;
 ;; Copyright © Carl Worth
 ;;