Fixes <https://issues.guix.gnu.org/58927>.
Reported by Maxime Devos <maximedevos@telenet.be>
and Marius Bakke <marius@gnu.org>.
Starting from 076e825dc5d585943ce820a279fffe4af09757fb, "guix --version"
would print "0" as the version number, due to '%guix-version' being
inlined in (guix ui) when compiling '*core-modules*' in (guix self).
* guix/self.scm (make-config.scm): Pass #:declarative? #f.