OS X package installation issue: Can't find gfortran 4.8 to build package

Question

I have an issue on mac os x El Capitan with Xcode 7. I\'m using fortran 6.1, downloaded from https://gcc.gnu.org/wiki/GFortranBinaries. I tried degrading to fortran 4.8. but

Answer 1

Following: Unable to install fortran based packages in R - "gfortran -m32:not found"

I installed gfortran 6.1 from https://gcc.gnu.org/wiki/GFortranBinaries#MacOS

Then, I added the following to the file ~/.R/Makevars within my home directory pointing to my gfortran installation:

F77 = gfortran
FC = gfortran
FLIBS = -L/usr/local/gfortran/lib