Instructions for cutting the Emacs release branch

1.  In the clone of the Emacs Git repository, switch to the 'master'
    branch, "git pull", and build it (using 'make bootstrap') to make
    sure it's not broken.  Run 'make check-expensive' and ensure all
    tests pass.  (Alternatively, verify that the automated build
    servers are showing success for the latest revision.)

2.  Create the release branch and switch to it.  Assuming that it is
    for releasing Emacs versions XY.1, XY.2, etc., the command is:

     git checkout -b emacs-XY

3.  Switch the release branch to the suitable version.  The convention
    is that release branches start with version XY.0.60, whereas the
    master branch from which the release branch was cut was at the
    version XY.0.50.  To change the version, do the following inside
    Emacs:

     M-x load-file RET admin/admin.el RET
     M-x set-version RET XY.0.60 RET

    Change the value of 'customize-changed-options-previous-release'
    in cus-edit.el to reference the last release from the emacs-XY-1
    branch (last release for the previous major version).

    The above modifies several files in the tree; commit the changes
    with the appropriate log message, something like "Bump Emacs
    version to XY.0.60", and with header saying "Cut the emacs-XY
    release branch".  Then push the changes:

     git push --set-upstream origin emacs-XY

    The "push" command should show the new branch just created.

4.  Switch back to the master branch.

     git checkout master
     git pull

    Set the version on the master branch to the next major release:

     M-x set-version RET XY+1.0.50 RET

    This creates a new file etc/NEWS.  "git add" it.
    (The original NEWS gets renamed into NEWS.XY.)

    Change the value of 'customize-changed-options-previous-release'
    in cus-edit.el to reference emacs-XY.1, the next version to be
    released from the newly-committed release branch.

    Update the emacs-module sources for the new version XY+1.  This
    entails:

     . adding a new file src/module-env-XY+1.h, with contents just the
       comment taken from the beginning of src/module-env-XY.h
     . removing the comment from the beginning of src/module-env-XY.h
     . adding two lines to configure.ac:

       AC_SUBST_FILE([module_env_snippet_XY+1])
       module_env_snippet_XY+1="$srcdir/src/module-env-XY+1.h"

     . adding a new 'struct emacs_env_XY+1' to src/emacs-module.h.in,
       with the contents identical to 'struct emacs_env_XY', with one
       line added:

         @module_env_snippet_XY+1@

     (FIXME: "M-x set-version" should do this emacs-module stuff
     automatically when the version is NN.0.60, or when there's no
     src/module-env-NN.h file.)

    "git add" the new src/module-env-XY+1.h file.

    Then rebuild Emacs.  Then commit the new/changed files and push.

5.  Announce the new release branch on emacs-devel.