$ sudo port -d install tbb
DEBUG: Found port in file:///opt/local/var/macports/sources/www.macports.org/files/ports/devel/tbb
DEBUG: Changing to port directory: /opt/local/var/macports/sources/www.macports.org/files/ports/devel/tbb
DEBUG: OS Platform: darwin
DEBUG: OS Version: 8.11.0
DEBUG: Mac OS X Version: 10.4
DEBUG: System Arch: powerpc
DEBUG: setting option os.universal_supported to yes
DEBUG: org.macports.load registered provides 'load', a pre-existing procedure. Target override will not be provided
DEBUG: org.macports.distfiles registered provides 'distfiles', a pre-existing procedure. Target override will not be provided
DEBUG: 'universal_variant no' specified, so not adding the default universal variant
DEBUG: Requested variant powerpc is not provided by port tbb.
DEBUG: Requested variant darwin is not provided by port tbb.
DEBUG: Requested variant macosx is not provided by port tbb.
--->  Computing dependencies for tbb
DEBUG: Executing org.macports.main (tbb)
DEBUG: Skipping completed org.macports.fetch (tbb)
DEBUG: Skipping completed org.macports.checksum (tbb)
DEBUG: Skipping completed org.macports.extract (tbb)
DEBUG: Skipping completed org.macports.patch (tbb)
--->  Configuring tbb
DEBUG: Using compiler 'Mac OS X gcc 4.0'
DEBUG: Executing org.macports.configure (tbb)
Error: Target org.macports.configure returned: can't read "arch_flag": no such variable
DEBUG: Backtrace: can't read "arch_flag": no such variable
    while executing
"$procedure $targetname"
Warning: the following items did not execute (for tbb): org.macports.activate org.macports.configure org.macports.build org.macports.destroot org.macports.install
Error: Status 1 encountered during processing.
To report a bug, see <http://guide.macports.org/#project.tickets>