I am trying to compile fftw3 with the openmp option under mac os Lion.
As exposed in http://www.fftw.org/release-notes.html, I use the following
command line
./configure --prefix=/Users/rveltz/laptopDante/Build/fftw-3.3 --enable-openmp
from my Download directory

The configure stops at the line:
checking for OpenMP flag of C compiler... unknown
configure: error: don't know how to enable OpenMP

I know that openmp is given with xcode but I don't know how to give it to configure option, does anybody can help me please?

Thank you,

I have Xcode 4.2, gcc 4.2.1