etc: Add 'indent-package.el' script.

* configure.ac: Check for 'emacs', substitute 'EMACS', and emit
'etc/indent-package.el'.
* etc/indent-package.el.in: New file.
* doc/contributing.texi (Formatting Code): Mention
'etc/indent-package.el'.
(Submitting Patches): Likewise, and link to the above node.

Co-authored-by: Alex Kost <alezost@gmail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 676f600111e..f628fa9d0d2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -232,6 +232,10 @@ AM_MISSING_PROG([DOT], [dot])
 dnl Manual pages.
 AM_MISSING_PROG([HELP2MAN], [help2man])
 
+dnl Emacs (optional), for 'etc/indent-package.el'.
+AC_PATH_PROG([EMACS], [emacs], [/usr/bin/emacs])
+AC_SUBST([EMACS])
+
 AC_CONFIG_FILES([Makefile
                  po/guix/Makefile.in
                  po/packages/Makefile.in
@@ -241,5 +245,6 @@ AC_CONFIG_FILES([scripts/guix], [chmod +x scripts/guix])
 AC_CONFIG_FILES([test-env:build-aux/test-env.in], [chmod +x test-env])
 AC_CONFIG_FILES([pre-inst-env:build-aux/pre-inst-env.in],
   [chmod +x pre-inst-env])
+AC_CONFIG_FILES([etc/indent-package.el], [chmod +x etc/indent-package.el])
 
 AC_OUTPUT