Bozhidar Batsov <bozhidar@batsov.com> writes:

> I might be missing something here, but what exactly is so problematic -
> there are packages that are in Emacs and on ELPA (e.g. cl-lib) and I don't
> think they are taking any special measures.

The problem is that seq.el (in Emacs) uses `pcase-defmacro', which does
not exist in Emacs 24.5.  When byte-compiling the file, we get warnings
as the byte compiler will think that `pcase-defmacro' is a function.

The solution I'm going for is to define locally the macro (when
byte-compiling the file in Emacs < 25), using something like the
following:

    (push `(pcase-defmacro . ,(lambda (&rest _) nil))
          byte-compile-macro-environment)

You can read more about the issue here:
https://github.com/NicolasPetton/seq.el/issues/7

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr