Re: emacs26, ucs-normalize.el, Symbol’s function definition is void: regexp-opt-charset

[Glenn Morris]

Although a --without-x bootstrap does work (eg this is what the
hydra.nixos "tarball" job is), it's not clear to me why it works.
(Maybe something calls regexp-opt during bootstrap, which triggers an
autoload?) There is a problem, however, as shown by the fact that in a
--without-x build post-bootstrap, this fails:

./src/emacs -Q -batch -f batch-byte-compile lisp/international/ucs-normalize.el

Error: Symbol's function definition is void: regexp-opt-charset