Unconditionally reset load-path after dumping

* src/lread.c: (dump_path): Remove.
(load-path-default): Remove `changed' argument.
Do not set dump_path permanently.  Simplify.
(init_lread): Simplify.
(syms_of_lread): Remove dump_path.

* lisp/loadup.el (load-path): Warn if site-load or site-init changes it.
No more need to reset it when bootstrapping.

* doc/lispref/internals.texi (Building Emacs):
* doc/lispref/loading.texi (Library Search): Mention that site-load,
site-init cannot change load-path.

* INSTALL: No longer mention load-path and site-init/site-load.

* etc/NEWS: Mention this.

Fixes: debbugs:16107

3 files changed, 15 insertions, 6 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 9bdc35a112c..4f5ff0ecf44 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,9 @@
+2013-12-13  Glenn Morris  <rgm@gnu.org>
+
+        * internals.texi (Building Emacs):
+        * loading.texi (Library Search): Mention that site-load,
+        site-init cannot change load-path.
+
 2013-12-12  Glenn Morris  <rgm@gnu.org>
 
         * elisp.texi: Tweak dircategory.
diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi
index 06375c1e18e..8cbf3c4e14c 100644
--- a/doc/lispref/internals.texi
+++ b/doc/lispref/internals.texi
@@ -116,6 +116,11 @@ time.)
 expect in an ordinary unmodified Emacs.  If you feel you must override
 normal features for your site, do it with @file{default.el}, so that
 users can override your changes if they wish.  @xref{Startup Summary}.
+Note that if either @file{site-load.el} or @file{site-init.el} changes
+@code{load-path}, the changes will be lost after dumping.
+@xref{Library Search}.  To make a permanent change to
+@code{load-path}, use the @option{--enable-locallisppath} option
+of @command{configure}.
 
   In a package that can be preloaded, it is sometimes necessary (or
 useful) to delay certain evaluations until Emacs subsequently starts
diff --git a/doc/lispref/loading.texi b/doc/lispref/loading.texi
index 0505b67961d..48866a10687 100644
--- a/doc/lispref/loading.texi
+++ b/doc/lispref/loading.texi
@@ -361,12 +361,10 @@ add one or more directories to @code{load-path}.  For example:
 (push "~/.emacs.d/lisp" load-path)
 @end example
 
-  Dumping Emacs uses a special value of @code{load-path}.  If the
-value of @code{load-path} at the end of dumping is unchanged (that is,
-still the same special value), the dumped Emacs switches to the
-ordinary @code{load-path} value when it starts up, as described above.
-But if @code{load-path} has any other value at the end of dumping,
-that value is used for execution of the dumped Emacs also.
+  Dumping Emacs uses a special value of @code{load-path}.  If you use
+a @file{site-load.el} or @file{site-init.el} file to customize the
+dumped Emacs (@pxref{Building Emacs}), any changes to @code{load-path}
+that these files make will be lost after dumping.
 
 @deffn Command locate-library library &optional nosuffix path interactive-call
 This command finds the precise file name for library @var{library}.  It