Work around bug in Eigen 3.2.5
Work around bug in Eigen 3.2.5

See http://eigen.tuxfamily.org/bz/show_bug.cgi?id=1039

mhunter1/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,JuKa87/OpenMx,JuKa87/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,JuKa87/OpenMx,JuKa87/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,JuKa87/OpenMx,JuKa87/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx