export container=mmdebstrap-unshare environment variable in unshare-mode hooks

mmdebstrap

@@ -1654,6 +1654,9 @@ sub run_hooks {
         push @env_opts,
           ("MMDEBSTRAP_ESSENTIAL=" . (join " ", @{$essential_pkgs}));
     }
+    if ($options->{mode} eq 'unshare') {
+        push @env_opts, "container=mmdebstrap-unshare";
+    }
 
     # Unset the close-on-exec flag, so that the file descriptor does not
     # get closed when we exec
@@ -7412,7 +7415,7 @@ As a debootstrap wrapper to run it without superuser privileges but using Linux
 user namespaces instead. This fixes Debian bug #829134.
 
     $ mmdebstrap --variant=custom --mode=unshare \
-        --setup-hook='env container=lxc debootstrap unstable "$1"' \
+        --setup-hook='debootstrap unstable "$1"' \
         - debian-debootstrap.tar
 
 Build a non-Debian chroot like Ubuntu bionic:

tests/as-debootstrap-unshare-wrapper

@@ -35,15 +35,8 @@ if [ -n "$AUTOPROXY" ] && [ -x "$AUTOPROXY" ] && [ -e /tmp/.auto-apt-proxy-0 ];
 	chmod 644 "$TMP_APT_CONFIG"
 fi
 
-# debootstrap runs mount -t proc proc /proc which doesn't work in an unshared
-# namespace on privileged docker (like salsaci), so mount /proc manually
-# https://bugs.debian.org/1031222
-# https://salsa.debian.org/installer-team/debootstrap/-/merge_requests/91
 $prefix {{ CMD }} --variant=custom --mode={{ MODE }} \
-	--setup-hook='env '"${AUTOPROXY:+APT_CONFIG='$TMP_APT_CONFIG'}"' container=lxc debootstrap --variant={{ VARIANT }} unstable "$1" {{ MIRROR }}' \
-	--setup-hook='mount -o rbind /proc "$1/proc"' \
-	--setup-hook='chroot "$1" dpkg-reconfigure systemd || true' \
-	--setup-hook='umount --lazy "$1/proc"' \
+	--setup-hook='env '"${AUTOPROXY:+APT_CONFIG='$TMP_APT_CONFIG'}"' debootstrap --variant={{ VARIANT }} unstable "$1" {{ MIRROR }}' \
 	- /tmp/debian-mm.tar {{ MIRROR }}
 if [ -n "$AUTOPROXY" ] && [ -x "$AUTOPROXY" ] && [ -e /tmp/.auto-apt-proxy-0 ]; then
 	rm "$TMP_APT_CONFIG"