So here I've completely failed to fix the conda-build issues in #3 but also explored how to force f2py to use flang as the fortran compiler on Windows rather than built-in gfortran. That isn't working either.

The last commit seems to be using flang for the compile stage, but then choosing gfortran for a linking stage (or something like that). The resulting module does not run.

When we force f2py to use flang by setting ncompiler=flang in the ~/pydistutils.cfg file, we get the error (on Windows):

error: don't know how to compile C/C++ code on platform 'nt' with 'flang' compiler

Googling on that error message hasn't revealed much.