Switching to lexical scope and emacs using closure (instead of
lambda) broke argument printing with make magic.

Set text quoting style to get doc strings without unicode single
quotation marks to keep the regular expressions in
texi-docstring-magic working.

Revise the various `require`s to avoid spurious dependencies, and tweak
the code here and there to eliminate the remaining dependencies.

* coq/coq-db.el: Don't require proof-config nor proof-syntax.
(coq-build-opt-regexp-from-db): Avoid proof-regexp-alt-list.

* coq/coq-indent.el: Use lexical-binding.  Don't require coq-syntax.
Comment out all the code that's not used any more.
(coq-empty-command-p): Use forward-comment instead of
coq-find-not-in-comment-backward.  Fix paren typos.
(coq-script-parse-cmdend-forward, coq-script-parse-cmdend-backward):
Use forward-comment i.s.o proof-script-generic-parse-find-comment-end.
Use syntax-ppss i.s.o proof-buffer-syntactic-context.
(coq-find-current-start): Explicit case-fold-search i.s.o proof-looking-at.

* coq/coq-mode.el (coq-mode): Set comment-start/end.

* coq/coq-smie.el: Require coq-syntax explicitly.
(coq-smie-detect-goal-command, coq-smie-module-deambiguate):
Explicit case-fold-search i.s.o proof-looking-at.
(coq-indent-basic): New custom var.
(coq-smie-rules): Use it in case PG is not loaded.

* coq/coq-syntax.el: Don't require proof-syntax, proof-utils, and span.
(coq-goal-command-p): Use overlay-get i.s.o span-property.
(coq-save-command-regexp-strict, coq-save-command-regexp):
Use \` and regexp-opt i.s.o proof-anchor-regexp and proof-ids-to-regexp.
(coq-save-command-p): Explicit case-fold-search i.s.o proof-string-match.
(coq--regexp-alt-list-symb): Rename from proof-regexp-alt-list-symb.
Use mapconcat i.s.o proof-regexp-alt-list.
(coq-save-with-hole-regexp): Use regexp-opt i.s.o proof-regexp-alt-list.
(coq-goal-command-regexp, coq-goal-with-hole-regexp)
(coq-decl-with-hole-regexp, coq-defn-with-hole-regexp)
(coq-font-lock-keywords-1): Use mapconcat i.s.o proof-regexp-alt-list.
(coq-find-first-hyp, coq-detect-hyps-positions-in-goals):
Use current buffer i.s.o proof-goals-buffer.
(coq-with-altered-syntax-table): Fix broken use of unwind-protect.

* coq/coq.el (coq-detect-hyps-in-goals): Change buffer before calling
coq-find-first-hyp and coq-detect-hyps-positions-in-goals.
(coq-pg-setup): Use comment-start/end.

* generic/pg-goals.el: Require proof-script explicitly instead of
autoloading via proof-insert-sendback-command.

* generic/pg-pbrpm.el: Require proof-script explicitly instead of
autoloading via proof-insert-pbp-command.

* generic/pg-pgip.el: Require proof-script explicitly.

* generic/proof-depends.el: Require proof-script explicitly instead of
autoloading via pg-set-span-helphighlights.

* generic/proof-script.el (pg-set-span-helphighlights)
(proof-insert-pbp-command, proof-insert-sendback-command)
(proof-script-generic-parse-find-comment-end): Don't autoload.

* generic/proof-syntax.el (proof-ids-to-regexp): Simplify.

* lib/span.el (span-delete): η-reduce.

Move the part of coq.el that is not specific to ProofGeneral into coq-mode.el
to make `coq-mode` into a major mode that can work without PG.

* coq/coq-mode.el: New file, with code extracted from coq.el.
(coq-use-pg): New var.
(coq-near-comment-region): Complete rewrite.

* Makefile.devel (autoloads): Add `coq` to the scanned subdirectories.
* generic/proof-autoloads.el: Regenerate.

* generic/proof-site.el: Don't override pre-existing major-mode definitions.

* coq/coq-syntax.el (coq-init-syntax-table): Delete function.
Setup the syntax-table while loading coq-mode.el instead.

* coq/coq-system.el (coq-prog-name, get-coq-library-directory)
(coq-library-directory, coq-tags): Move to coq-mode.el.

* coq/coq.el: Set proof-assistant when loaded.
(coq-may-use-prettify, coq-outline-regexp)
(coq-outline-heading-end-regexp, coq-mode)
(coq-prettify-symbols-alist, coq-fill-paragraph-function)
(coq-adaptive-fill-function): Move to coq-mode.el.
(coq-shell-mode-syntax-table, coq-response-mode-syntax-table)
(coq-goals-mode-syntax-table): Just reuse the already setup
coq-mode-syntax-table...
(coq-shell-mode-config, coq-goals-mode-config, coq-response-config):
... instead of calling coq-init-syntax-table.
(coq-get-comment-region): Delete, not used any more.
(coq-pg-mode-map): New var.  Move top-level keymap setup here.
(coq-pg-setup): Rename from coq-mode-config.
Move all the non-PG specific settings to coq-mode.

* generic/proof-script.el (proof-mode): Simplify call to
proof-splash-message since it does the same extra tests internally.
(proof-config-done-related): Don't touch font-lock-defaults if the mode
doesn't provide any font-lock-defaults.

* isar/isar-syntax.el: Use lexical-binding.
(isar-font-lock-fontify-syntactically-region): Make it
callable from font0lock-keywords.
(isar-font-lock-keywords-1):
Call isar-font-lock-fontify-syntactically-region.

* generic/proof-syntax.el (font-lock-fontify-keywords-region):
Remove advice.
(proof-ids): Remove, unused.

* lib/bufhist.el (bufhist-erase-buffer):
Don't let-bind after-change-functions.

* generic/pg-pbrpm.el (pg-pbrpm-auto-select-around-point):
Fix one more left-over cl.el use.

* generic/proof-utils.el (proof-with-script-buffer): Add edebug spec.

Fix a few more cl.el leftovers.  Get rid of remaining use of iso-2022.
Use SMIE unconditionally.

* coq/coq-abbrev.el: Use lexical-binding.
(coq-install-abbrevs): Delete, only keep the relevant contents.
(proof-defstringset-fn): Remove.  Fold changes into the main version.

* coq/coq-indent.el (coq-find-real-start): Use forward-comment.

* coq/coq-smie.el: Use lexical-binding.  Assume `smie` is available.
(coq--string-suffix-p): Rename from coq-string-suffix-p.
Use string-suffix-p for it when available.
(string-suffix-p): Never define here.  Change all users to use
coq--string-suffix-p instead.
(coq-smie-.-deambiguate): Use forward-comment.  Remove unused var `beg`.
(coq-backward-token-fast-nogluing-dot-friends)
(coq-forward-token-fast-nogluing-dot-friends): Remove unused var
`tok-other`.
(coq-smie-search-token-backward): Remove unused var `p`.
(coq-smie-:=-deambiguate, coq-smie-backward-token): Prefer char-before
over looking-back.
(coq-smie-rules): Use `pcase` over deprecated cl's `case`.

* coq/coq-syntax.el: Use lexical-binding.
(coq-count-match): Rewrite so it doesn't do needless heap-allocation.
(coq-module-opening-p, coq-section-command-p, coq-goal-command-str-p):
Use case-fold-search rather than proof-string-match.
(coq-goal-command-regexp): Forward-declare.
(coq-save-command-regexp-strict): Move before first use.
(coq-reserved-regexp): Use a single \_< ... \_>.
(coq-detect-hyps-positions): Limit search for looking-back.

* coq/coq.el: Remove SMIE declarations since SMIE is always used.
(coq-use-smie): Remove, unused.
(coq-smie): Always require.

* generic/pg-pbrpm.el: Fix leftover cl.el uses.

* generic/proof-utils.el (proof-defstringset-fn): Fix copy&paste error
in the docstring, improve interactive prompt.

* lib/maths-menu.el: Use utf-8 and lexical-binding.

Use lexical-binding in a few files where it was easy.
Don't require `proof-compat` when it's not used.

* coq/coq-db.el: Use lexical-binding.

* coq/coq-system.el: Use lexical-binding.
(coq--extract-prog-args): Use concatenated-args rather than recomputing it.

* coq/coq.el: Require `span` to silence some warnings.

* generic/pg-user.el: Use lexical-binding.
(complete, add-completion, completion-min-length): Silence warnings.

* generic/pg-xml.el: Use lexical-binding.
(pg-xml-string-of): Prefer mapconcat to reduce+concat.

* generic/proof-depends.el: Use lexical-binding.
(proof-dep-split-deps): Use `push`.

* generic/proof-shell.el: Require `span` to silence some warnings.
(proof-shell-invisible-command): Don't use lexical-let just to build
a wasteful η-redex!

* lib/holes.el: Use lexical-binding.
Remove redundant :group args.

* lib/span.el: Use lexical-binding.
(span-read-only-hook): Use user-error.
(span-raise): Remove, unused.

Move `defvar`s used to silence warnings outside of eval-when-compile.
Make sure they don't actually give a value to the var.

* pg-init.el: Simplify.
Use (if t ...) to avoid running `require` at compile-time.
Don't add subdirs to load-path here since this code is never used.
(pg-init--script-full-path, pg-init--pg-root):
Inline their definition into their sole user.

* generic/proof-utils.el (proof-resize-window-tofit):
Inline definitions of window-leftmost-p and window-rightmost-p previously
in proof-compat.el.

* lib/proof-compat.el (proof-running-on-win32): Remove, not used.
(mac-key-mode): Remove, there's no carbon-emacs-package-version in
Emacs≥24.3.
(pg-custom-undeclare-variable): Use dolist.
(save-selected-frame): Remove, save-selected-window also saves&restores
the selected frame at the same time.  Update all users (which already
used save-selected-window around it).
(window-leftmost-p, window-rightmost-p, window-bottom-p)
(find-coding-system): Remove, unused.

* hol-light/hol-light.el (caml-font-lock-keywords): Don't try to defvar
it to a dummy value and...
(hol-light): ...check its existence before using it instead.

* coq/coq.el (coq-may-use-prettify): Simplify initialization.