Archive mode broken after the latest updates

[Guido Soranzio]

An update to my previous report.

I think that the issue is due to the changeset 23238 and how
the new procedures command_exec and parse_environment in portutil.tcl
are managing the unarchive.env variable and the pipes.

With the release 1.4.0 of MacPorts, the assembled command was

'cd "/opt/local/var/db/dports/build/
_opt_local_var_db_dports_sources_rsync.rsync.darwinports.org_dpupdate_dp 
orts_archivers_unrar
/work/destroot" && /usr/bin/gzip -d -c /opt/local/var/db/dports/ 
packages/darwin/powerpc/
unrar-3.7.4_0.powerpc.tgz | /usr/bin/tar -xvpf -'


With the latest sources, the content of unarchive.env (the gzip command)
is missing from the pipe:

'cd "/opt/local/var/db/dports/build/
_opt_local_var_db_dports_sources_rsync.rsync.darwinports.org_dpupdate_dp 
orts_archivers_unrar/
work/destroot" && /usr/bin/tar -xvpf -'.