eigen3 install problems

[Brickle Macho]

Hi all,

I started from a new clean macport install. Downloaded the package,
installed. Then installed python27, then tried to install opencv with
python bindings:

% sudo port install opencv +python27

After a little investigation I discovered it fails installing eigen3.
When I try the following:

% sudo port install -v eigen3

I see it fails with the following extract from highlighting the error:
------
/usr/local/bin/gfortran -L/opt/local/lib -arch x86_64 -pipe -O2 -m64
CMakeFiles/cmTryCompileExec.dir/testFortranCompiler.f.o -o cmTryCompileExec


gfortran: error: x86_64: No such file or directory

gfortran: error: unrecognized option ‘-arch’

gmake[1]: *** [cmTryCompileExec] Error 1

gmake[1]: Leaving directory
`/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_math_eigen3/eigen3/work/3.0.1-x86_64/CMakeFiles/CMakeTmp'


gmake: *** [cmTryCompileExec/fast] Error 2
-------


Figuring is some gfortran instal in /usr/local/bin, issue I try install
gfortran from macports

% sudo port install gcc46 +gfortran

This appears to install correctly, no errors. So I try to install
eigen3, I clean it first just in case:

% sudo port clean eigne3
% sudo port -v install eigen3

from the error message it appears to be macports gfortran but is still
fails. Extract of verbose output follows:

----
/opt/local/bin/gfortran -L/opt/local/lib -arch x86_64 -pipe -O2 -m64
CMakeFiles/cmTryCompileExec.dir/testFortranCompiler.f.o -o cmTryCompileExec


gfortran: error: x86_64: No such file or directory

gfortran: error: unrecognized option '-arch'

gmake[1]: *** [cmTryCompileExec] Error 1
-----

Any ideas how to fix the problem?