error building goes on Lion

[Mr. Puneet Kishor]

at the end of a rather large log file, I get

:info:build libtool: link: /Developer/usr/bin/llvm-g++-4.2 -dynamiclib  -o .libs/libgeos-3.3.1.dylib  .libs/inlines.o   -Wl,-force_load,algorithm/.libs/libalgorithm.a -Wl,-force_load,geom/.libs/libgeom.a -Wl,-force_load,geomgraph/.libs/libgeomgraph.a -Wl,-force_load,index/.libs/libindex.a -Wl,-force_load,io/.libs/libio.a -Wl,-force_load,linearref/.libs/liblinearref.a -Wl,-force_load,noding/.libs/libnoding.a -Wl,-force_load,operation/.libs/liboperation.a -Wl,-force_load,planargraph/.libs/libplanargraph.a -Wl,-force_load,precision/.libs/libprecision.a -Wl,-force_load,simplify/.libs/libsimplify.a -Wl,-force_load,util/.libs/libutil.a  -L/opt/local/lib  -O2 -arch x86_64 -arch x86_64   -install_name  /opt/local/lib/libgeos-3.3.1.dylib  -Wl,-single_module
:info:build Undefined symbols for architecture x86_64:
:info:build   "__ZNSt8auto_ptrIN4geos4geom8EnvelopeEEcvSt12auto_ptr_refIT_EIS2_EEv", referenced from:
:info:build       virtual thunk to geos::geom::GeometryCollection::computeEnvelopeInternal() constin libgeom.a(GeometryCollection.o)
:info:build   "std::auto_ptr<geos::geom::Envelope>::auto_ptr(std::auto_ptr_ref<geos::geom::Envelope>)", referenced from:
:info:build       virtual thunk to geos::geom::GeometryCollection::computeEnvelopeInternal() constin libgeom.a(GeometryCollection.o)
:info:build ld: symbol(s) not found for architecture x86_64
:info:build collect2: ld returned 1 exit status
:info:build make[2]: *** [libgeos.la] Error 1
:info:build make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_geos/geos/work/geos-3.3.1/src'
:info:build make[1]: *** [all-recursive] Error 1
:info:build make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_geos/geos/work/geos-3.3.1/src'
:info:build make: *** [all-recursive] Error 1
:info:build make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_geos/geos/work/geos-3.3.1'
:info:build shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_geos/geos/work/geos-3.3.1" && /usr/bin/make -j4 -w all " returned error 2
:error:build Target org.macports.build returned: shell command failed (see log for details)
:debug:build Backtrace: shell command failed (see log for details)
    while executing
"command_exec build"
    (procedure "portbuild::build_main" line 8)
    invoked from within
"$procedure $targetname"
:info:build Warning: the following items did not execute (for geos): org.macports.install org.macports.build org.macports.destroot
:notice:build Log for geos is at: /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_geos/geos/main.log

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Puneet Kishor