I'm climbing the walls with this one:

I get this error message
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Couldn't find gfortran

You must set the TM_FORTRAN variable to the full path of your Fortran compiler (e.g./usr/local/bin/gfortran). You may also set TM_FFLAGS for any Fortran compiler options.

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but cannot find out anywhere how to edit the TM_FORTRAN variable. Can anyone help please ? 

[ gfortran is working fine from Terminal. ]

Thanks

Peter