Well you may be trying to build with gcc-7 but you are building C++ with clang
gmake[2]: Leaving directory '/Users/markadams/Codes/petsc/arch-macosx-gnu-g-omp/externalpackages/mpich-3.3a3' gmake[1]: Leaving directory '/Users/markadams/Codes/petsc/arch-macosx-gnu-g-omp/externalpackages/mpich-3.3a3'clang: error: unsupported option '-fopenmp' --with-cc++=gcc-7 is not correct. > On Jan 26, 2018, at 5:21 PM, Mark Adams <[email protected]> wrote: > > I get this error on osx. I am trying to build with OpenMP (gcc-7). > <configure.log>
