Generating a single byte-compiled file from more sources

Question

I have a relatively large elisp file which starts becoming hard to maintain and I am going to split it into smaller files.

However, for my use case, it would be still convenient to have a single byte-compiled file (because I use it on other systems and it is simpler to copy a single file).

Of course, I could concatenate all source files into a single foo.el file and compile the latter.
Before going this way, I would like to know if there is already a function along the lines of:

(byte-compile-directory foo-dir foo)

generating a single foo.elc from sources in foo-dir.

Answer 1

There is byte-recompile-directory, but it does not produce a single .elc.

Consider putting the files in the same, dedicated directory; using byte-recompile-directory (after compiling each file once); and zipping the directory into a .zip archive or similar.

One command to byte-compile everything, one command to zip it all up, and one to unzip it at the destination. (And you can combine the first two commands into one.)

Answer 2

Another possibility below.

se-load-chunks loads all the source files set by the variable chunks.
se-make-single creates the unique source file single.el.
se-compile both makes a single.el and compiles it.

;; compile-help.el

(defvar chunks (list "chunk1"
                     "chunk2"))

(defun se-load-chunks ()
  (mapc (lambda (file) (load (se-make-path file))) chunks))

(defun se-make-single ()
  (let ((dst (se-make-path "single")))
    (if (file-exists-p dst) (delete-file dst))
    (mapc (lambda (chunk)
            (se-append-file dst (se-make-path chunk)))
          chunks)))

(defun se-compile ()
  (interactive)
  (se-make-single)
  (byte-compile-file (se-make-path "single")))

(defun se-append-file (destination source)      
  (with-temp-buffer (insert-file-contents source)
        (append-to-file (point-min) (point-max) destination)))

(defun se-make-path (file)
  "Make path"
  (expand-file-name (concat file ".el")))

Update Implemented @Basil suggestions.
Replace the se- namespace with something better.