Do not rebuild Org when using multiple build caches

[raxod502]

We sometimes have the same straight.el repository directory used with multiple build caches, for example when using the CI tooling from Radian to test the configuration against a different Emacs version from the host system, without having to redownload hundreds of MB of packages again (just need to recompile them, with a separate build directory and build cache). However, this causes some issues where having one instance of straight.el build Org triggers a modification in every other straight.el instance for that repository, because the pre-build step updates mtimes in the repository.

Not sure if this is something we can or should fix, but noting it down as it's a significant annoyance for me (building Org takes a long time).

[raxod502]

straight.el/straight.el

Lines 3744 to 3775 in b7da472

	(defun straight-recipes-org-elpa--build ()
	"Generate `org-version.el`.
	This is to avoid relying on `make` on Windows.
	See: https://github.com/radian-software/straight.el/issues/707"
	(let* ((default-directory (straight--repos-dir "org" "lisp"))
	(emacs (straight--emacs-path))
	(orgversion
	(straight--process-with-result
	(straight--process-run
	emacs "-Q" "--batch"
	"--eval" "(require 'lisp-mnt)"
	"--visit" "org.el"
	"--eval" "(princ (lm-header \"version\"))")
	(when failure (error "Failed to parse ORGVERSION: %S" result))
	(string-trim (replace-regexp-in-string "-dev" "" stdout))))
	(gitversion
	(straight--process-with-result
	(straight--process-run "git" "describe" "--match" "release*"
	"--abbrev=6" "HEAD")
	(if success (string-trim stdout) "N/A"))))
	(call-process
	emacs nil straight-byte-compilation-buffer nil
	"-Q" "--batch"
	"--eval" "(setq vc-handled-backends nil org-startup-folded nil)"
	"--eval" (format "(add-to-list 'load-path %S)" default-directory)
	"--eval" "(load \"org-compat.el\")"
	"--eval" "(load \"../mk/org-fixup.el\")"
	;; Do we want autoloads here, or should straight handle it?
	"--eval" "(org-make-org-loaddefs)"
	"--eval" (format "(org-make-org-version %S %S)" orgversion gitversion)
	"--eval" "(cd \"../doc\")"
	"--eval" "(org-make-manuals)")))

[mcmillanbb]

I also run into this issue.
The setup I have that causes this is that I sometime want to run emacs in -q mode, to debug this or that issue. But of course, this disables straight, and it then becomes a pain to load whatever package I want to test. So I have a separate init file (directory) with the minimum bootstrapping for straight, which I open by pointing emacs at with the --init-directory flag.

The problem is that whenever I open this other init-directory, it does what you say, and has to rebuild everything. And then again when I open a normal emacs session.

Now it is possible that you can just tell me to use a different set up, in which case I am all ears. But as it is, it can take quite a while to switch between the two.