liburcu: port extract is broken

[barracuda156]

--->  Extracting userspace-rcu-0.14.0.tar.bz2
Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_liburcu/liburcu/work" && /usr/bin/gzip -dc '/opt/local/var/macports/distfiles/liburcu/userspace-rcu-0.14.0.tar.bz2' | /usr/bin/gnutar --no-same-owner -xf - 

gzip: /opt/local/var/macports/distfiles/liburcu/userspace-rcu-0.14.0.tar.bz2: not in gzip format
--->  Configuring liburcu
Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_liburcu/liburcu/work/userspace-rcu-0.14.0" && ./configure --prefix=/opt/local 
sh: ./configure: No such file or directory
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_liburcu/liburcu/work/userspace-rcu-0.14.0" && ./configure --prefix=/opt/local 
Exit code: 127

It tries to use a wrong command for extract.

[jmroot (Joshua Root)]

In 0f78bcc9168abdd9835205cd99082ce18c3c18c0/macports-ports (master):

liburcu: fix extract command

Closes: #70443

[danielluke (Daniel J. Luke)]

Thanks - newer tar manages this transparently so I missed it.