etc: indent-code.el: Use the --quick option.

This prevents Emacs from loading the autoload definitions found in its
profile, which needlessly clutters the output.  It also prevents Geiser (if
installed) from blocking the script and asking the user to input the Scheme
implementation to use.

The trick for passing multiple arguments to Emacs is to use what is called a
"sesquicolon" (see https://www.emacswiki.org/emacs/EmacsScripts).

* etc/indent-code.el.in: Rename to...
* etc/indent-code.el: ...this.  Adapt the shebang to use a sesquicolon, and
pass the --quick option to Emacs.  Since this line is interpreted by the
shell, simply use Emacs from the PATH instead of from a hard coded location.
(main): New procedure, used as the entry point.
* configure.ac: Remove the warning about Emacs.  Emacs can now be installed
any time by the user if they want to use the script.
* .gitignore: No longer ignore changes to etc/indent-code.el.

3 files changed, 27 insertions, 35 deletions

diff --git a/.gitignore b/.gitignore
index fd2cf56098..cc5ceb5e10 100644
--- a/.gitignore
+++ b/.gitignore
@@ -149,7 +149,6 @@ stamp-h[0-9]
 tmp
 /doc/os-config-lightweight-desktop.texi
 /nix/scripts/download
-/etc/indent-code.el
 /.version
 /doc/stamp-[0-9]
 /gnu/packages/bootstrap
diff --git a/configure.ac b/configure.ac
index a44a605dc0..0a20b476eb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -286,15 +286,6 @@ dnl Documentation translation.
 AM_MISSING_PROG([PO4A_TRANSLATE], [po4a-translate])
 AM_MISSING_PROG([PO4A_UPDATEPO], [po4a-updatepo])
 
-dnl Emacs (optional), for 'etc/indent-code.el'.
-AC_PATH_PROG([EMACS], [emacs])
-if test "x$EMACS" = x; then
-    AC_MSG_WARN([Please install GNU Emacs to use etc/indent-code.el.])
-else
-    AC_SUBST([EMACS])
-    AC_CONFIG_FILES([etc/indent-code.el], [chmod +x etc/indent-code.el])
-fi
-
 case "$storedir" in
   /gnu/store)
     ;;
diff --git a/etc/indent-code.el.in b/etc/indent-code.el
index 6102b5d1ab..255ffb126b 100755
--- a/etc/indent-code.el.in
+++ b/etc/indent-code.el
@@ -1,8 +1,9 @@
-#!@EMACS@ --script
+:;exec emacs --batch --quick --load="$0" --funcall=main "$@"
 ;;; indent-code.el --- Run Emacs to indent a package definition.
 
 ;; Copyright © 2017 Alex Kost <alezost@gmail.com>
 ;; Copyright © 2017 Ludovic Courtès <ludo@gnu.org>
+;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 
 ;; This file is part of GNU Guix.
 
@@ -86,29 +87,30 @@
  (with-syntax 1))
 
 
-(pcase command-line-args-left
-  (`(,file-name ,package-name)
-   ;; Indent the definition of PACKAGE-NAME in FILE-NAME.
-   (find-file file-name)
-   (goto-char (point-min))
-   (if (re-search-forward (concat "^(define\\(-public\\) +"
-                                  package-name)
-                          nil t)
-       (let ((indent-tabs-mode nil))
-         (beginning-of-defun)
-         (indent-sexp)
-         (save-buffer)
-         (message "Done!"))
-     (error "Package '%s' not found in '%s'"
-            package-name file-name)))
-  (`(,file-name)
-   ;; Indent all of FILE-NAME.
-   (find-file file-name)
-   (let ((indent-tabs-mode nil))
-     (indent-region (point-min) (point-max))
-     (save-buffer)
-     (message "Done!")))
-  (x
-   (error "Usage: indent-code.el FILE [PACKAGE]")))
+(defun main ()
+  (pcase command-line-args-left
+    (`(,file-name ,package-name)
+     ;; Indent the definition of PACKAGE-NAME in FILE-NAME.
+     (find-file file-name)
+     (goto-char (point-min))
+     (if (re-search-forward (concat "^(define\\(-public\\) +"
+                                    package-name)
+                            nil t)
+         (let ((indent-tabs-mode nil))
+           (beginning-of-defun)
+           (indent-sexp)
+           (save-buffer)
+           (message "Done!"))
+       (error "Package '%s' not found in '%s'"
+              package-name file-name)))
+    (`(,file-name)
+     ;; Indent all of FILE-NAME.
+     (find-file file-name)
+     (let ((indent-tabs-mode nil))
+       (indent-region (point-min) (point-max))
+       (save-buffer)
+       (message "Done!")))
+    (x
+     (error "Usage: indent-code.el FILE [PACKAGE]"))))
 
 ;;; indent-code.el ends here