Hdf5-1.10.2 gfortran build with Cmake, MinGW on Windows

The subject says it all.
I’m trying to build gfortran libraries for hdf5-1.10.2 with Cmake using MinGW on Windows. I’m following the recipe here:

Cmake 3.12 is installed, and HDF5 files extracted from Cmake-hdf5-1.10.2.zip.
Now I need to edit files to add MinGW as a BUILD_GENERATOR option.
As I understand, I need to edit the HDF5config.cmake file, then create a ‘build-gfortran-64.bat’ file referencing my BUILD_GENERATOR option (plus --enable-fortran flag).
I added the following to HDF5config.cmake :

    set (CTEST_CMAKE_GENERATOR "MinGW Makefiles")
    set (SITE_OS_BITS "64")
    set (SITE_COMPILER_NAME "gfortran")

And this is my 1 line bat file:
ctest -S HDF5config.cmake,BUILD_GENERATOR=MinGW --enable-fortran -C Release -V -O hdf5.log

When I run, I get a bunch of messages ending with:
No tests were found!!!

The Build folder was created, but not much else.
What am I missing? Thanks!