Importing host-side (json …) modules would make builds dependent on the
Guile-JSON version currently installed by the user. Use
‘with-extensions’ instead.
* guix/build-system/composer.scm (%composer-build-system-modules):
Remove (json …) modules.
(composer-build)[guile-json]: New variable.
[builder]: Wrap body in ‘with-extensions’.
Change-Id: Ibe565572d60481b31292d73c6fa23d42aa3ceecb