sys-apps/guix: add check for USER_NS

guix-daemon uses user namespaces to build derivations
and create interactive environments in
'guix environment --container'.

Package-Manager: Portage-2.3.76, Repoman-2.3.17
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

sys-apps/guix/guix-1.0.1.ebuild

@@ -3,7 +3,7 @@
 
 EAPI=7
 
-inherit autotools readme.gentoo-r1 systemd user
+inherit autotools linux-info readme.gentoo-r1 systemd user
 
 DESCRIPTION="GNU package manager (nix sibling)"
 HOMEPAGE="https://www.gnu.org/software/guix/"
@@ -90,6 +90,13 @@ Next steps:
 	guix package manager user manual: https://www.gnu.org/software/guix/manual/guix.html
 "
 
+pkg_pretend() {
+	# USER_NS is used to run builders in a default setting in linux
+	# and for 'guix environment --container'.
+	local CONFIG_CHECK="~USER_NS"
+	check_extra_config
+}
+
 pkg_setup() {
 	enewgroup guixbuild
 	for i in {1..10}; do