Operating System OSX 10.8.3 Xcode v4.6.1 MPICH 3.0.4 macports % port list automake libtool autoconf gcc47 automake @1.13.1 devel/automake libtool @2.4.2 devel/libtool autoconf @2.69 devel/autoconf gcc47 @4.7.3 lang/gcc47 ========================== My first attempt ============================= setenv CC "gcc-mp-4.7 -m64" setenv FC "gfortran-mp-4.7 -m64" setenv F77 "gfortran-mp-4.7 -m64" setenv F90 "gfortran-mp-4.7 -m64" ./configure --prefix=$HOME/mpi3gnu473 --enable-fc --disable-cxx --with-device=ch3:nemesis ... configure: ===== done with src/openpa configure ===== ... configure: error: F90 and F90FLAGS are replaced by FC and FCFLAGS respectively in this configure, please unset F90/F90FLAGS and set FC/FCFLAGS instead and rerun configure again Remarks: While odd, this is at least says what it wants. ========================== My second attempt ============================= unsetenv F77 unsetenv F90 ./configure --prefix=$HOME/mpi3gnu473 --enable-fc --disable-cxx --with-device=ch3:nemesis ... configure: ===== done with src/openpa configure ===== ... configure: error: **** Incompatible Fortran and C Object File Types! **** F77 Object File Type produced by "gfortran -O2" is : : Mach-O object i386. C Object File Type produced by "gcc-mp-4.7 -m64 -O2" is : : Mach-O 64-bit object x86_64. Remark: sometimes I see "gfortran", sometimes I see "gfortran-mp-4.7 -m64" ========================== My third attempt ============================= setenv FC "gfortran-mp-4.7" setenv FCFLAGS "-m64" ./configure --prefix=$HOME/mpi3gnu473 --enable-fc --disable-cxx --with-device=ch3:nemesis ... configure: ===== done with src/openpa configure ===== ... configure: error: **** Incompatible Fortran and C Object File Types! **** F77 Object File Type produced by "gfortran -O2" is : : Mach-O object i386. C Object File Type produced by "gcc-mp-4.7 -m64 -O2" is : : Mach-O 64-bit object x86_64. Remark: Well, that didn't help. ========================== My workaround ============================= In the end I created a csh script called gfortran at the start of my path and simply made it execute gfortran-mp-4.7 -m64 $argv This built okay and runs just fine.