Don't store docstrings of preloaded .el files in etc/DOC

Since the location of those files changes between build time and
installation time, this requires to tweak the file name used in those
(#$ . NNN) references during the dump so they don't hardcode the build
directory.  We do it in the same way as was already done for those
same file names in `load-history`, except we convert them back to
absolute file names more lazily (i.e. when fetching the actual
docstring rather than at startup), which requires remembering the
`lisp-dir` computed at startup in the new `lisp-directory` variable.

* src/Makefile.in ($(etc)/DOC): Don't scan Lisp files any more.

* src/lread.c (Fload): Use relative file names for `load-file-name`
when preloading for the dump, like we already did for `current-load-list`.
(read_list): Don't zero-out dynamic docstring references during the
preload since they won't be filled later by Snarf-documentation any more.
(read1): Remove the hash-hack for doc references that were zeroed.

* lisp/startup.el (lisp-directory): New variable.
(command-line): Set it.

* src/doc.c (get_doc_string): Use `lisp-directory` for dynamic
docstring references using relative file names.
(syms_of_doc): Add `Qlisp_directory`.

* lib-src/make-docfile.c (scan_file): Don't handle `.el` or `.elc`
files any more.
(IS_SLASH): Remove macro, not used any more.
(skip_white, read_lisp_symbol, search_lisp_doc_at_eol)
(scan_lisp_file): Remove functions, not used any more.

* doc/lispref/loading.texi (Library Search): Mention `lisp-directory`.

1 files changed, 7 insertions, 7 deletions

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 11107ec0f6d..a64af022d4f 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -4926,13 +4926,13 @@ binding slots have been popped."
   ;; if it weren't for the fact that we need to figure out when a defalias
   ;; defines a macro, so as to add it to byte-compile-macro-environment.
   ;;
-  ;; FIXME: we also use this hunk-handler to implement the function's dynamic
-  ;; docstring feature.  We could actually implement it more elegantly in
-  ;; byte-compile-lambda so it applies to all lambdas, but the problem is that
-  ;; the resulting .elc format will not be recognized by make-docfile, so
-  ;; either we stop using DOC for the docstrings of preloaded elc files (at the
-  ;; cost of around 24KB on 32bit hosts, double on 64bit hosts) or we need to
-  ;; build DOC in a more clever way (e.g. handle anonymous elements).
+  ;; FIXME: we also use this hunk-handler to implement the function's
+  ;; dynamic docstring feature (via byte-compile-file-form-defmumble).
+  ;; We should actually implement it (more elegantly) in
+  ;; byte-compile-lambda so it applies to all lambdas.  We did it here
+  ;; so the resulting .elc format was recognizable by make-docfile,
+  ;; but since then we stopped using DOC for the docstrings of
+  ;; preloaded elc files so that obstacle is gone.
   (let ((byte-compile-free-references nil)
         (byte-compile-free-assignments nil))
     (pcase form