Improve documentation of pdumper; minor code cleanup

* src/emacs.c (usage_message): Add the --dump-file option.
(string_starts_with_p, find_argument): Functions removed; use
'argmatch' instead.
(PDUMP_FILE_ARG): Macro removed; use literal strings instead,
as with other command-line options.  Use HAVE_PDUMPER for cpp
conditionals which used PDUMP_FILE_ARG.
(load_pdump, main): Use 'argmatch' for "--dump-file" and
"--temacs" arguments, thus supporting the "-dump-file" and
"-temacs" variants, for consistency with other options.
(main): Remove the extra fatal error for using --dump-file in
unexec'ed Emacs: load_pdump does that anyway.
(standard_args): Add --dump-file and --temacs, with
appropriate priorities.

* etc/NEWS: Expand on the pdumper support.

* doc/emacs/cmdargs.texi (Initial Options): Document the
'--dump-file' command-line option.

1 files changed, 11 insertions, 0 deletions

diff --git a/doc/emacs/cmdargs.texi b/doc/emacs/cmdargs.texi
index d51d97b48a2..b49126764a6 100644
--- a/doc/emacs/cmdargs.texi
+++ b/doc/emacs/cmdargs.texi
@@ -383,6 +383,17 @@ verify that their module conforms to the module API requirements.  The
 option makes Emacs abort if a module-related assertion triggers.
 @xref{Writing Dynamic Modules,, Writing Dynamically-Loaded Modules,
 elisp, The GNU Emacs Lisp Reference Manual}.
+
+@item --dump-file=@var{file}
+@opindex --dump-file
+@cindex specify dump file
+Load the dumped Emacs state from the named @var{file}.  By default,
+Emacs will look for its dump state in a file named
+@file{@var{emacs}.pdmp} in the directory of the executable, where
+@var{emacs} is the name of the Emacs executable file, normally just
+@file{emacs}.  However, if you rename or move the dump file to a
+different place, you can use this option to tell Emacs where to find
+that file.
 @end table
 
 @node Command Example