Various follow-ups for early init file changes

* doc/emacs/custom.texi (Early Init File): Add more details about
which variables must be set in the early init file rather than the
regular init file.  See
https://lists.nongnu.org/archive/html/bug-gnu-emacs/2018-02/msg00827.html

* lisp/emacs-lisp/package.el (package-enable-at-startup): Update
docstring to note that packages are now made available before loading
the init file, rather than afterwards.  See
https://lists.gnu.org/archive/html/emacs-devel/2018-02/msg00632.html
(package-load-list): Refer to "making available" rather than "loading"
for packages.  See
https://lists.gnu.org/archive/html/emacs-devel/2018-02/msg00298.html

* lisp/startup.el (command-line): Call `custom-reevaluate-setting' on
predefined variables before loading the early init file and before
`package-initialize' is called.  This prevents
`Info-default-directory-list' from being unbound when
`package-initialize' tries to access it during startup.  See
https://lists.gnu.org/archive/html/emacs-devel/2018-02/msg00545.html

* lisp/emacs-lisp/package.el (package-initialize): Issue a warning
if called twice.
See: https://lists.gnu.org/archive/html/emacs-devel/2018-02/msg00626.html
     https://lists.gnu.org/archive/html/emacs-devel/2018-03/msg00301.html

1 files changed, 7 insertions, 3 deletions

diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index be73d7a289a..a69888cdbd6 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -2607,9 +2607,13 @@ desirable to have customizations that take effect during Emacs startup
 earlier than the normal init file is processed.  Such customizations
 can be put in the early init file, @file{~/.emacs.d/early-init.el}.
 This file is loaded before the package system is initialized, so in it
-you can customize variables that affect the initialization process,
-such as @code{package-enable-at-startup} and @code{package-load-list}.
-@xref{Package Installation}.
+you can customize variables that affect the package initialization
+process, such as @code{package-enable-at-startup},
+@code{package-load-list}, and @code{package-user-dir}.  Note that
+variables like @code{package-archives} which only affect the
+installation of new packages, and not the process of making
+already-installed packages available, may be customized in the regular
+init file.  @xref{Package Installation}.
 
   For more information on the early init file, @pxref{Init File,,,
 elisp, The Emacs Lisp Reference Manual}.