Yes, sorry, next time I will open a new thread. I actually already have a new problem, so I am going to post that in a new thread.
This particular problem here has been solved. I didn't manage to get it working with ifort (I guess there is no hope?) and with gfortran I noticed that the standard installation of this mingw was somehow 32bit. So I had to reinstall it using the 64bit version and then calling Fortran from Julia worked.