Attempt at using levmar

levmar.log

 download libblas.dll, libblas.lib, liblapack.dll, liblapack.lib from https://icl.cs.utk.edu/lapack-for-windows/lapack/#libraries_mingw to lib/

Add to `stack.yaml`:

extra-deps:
  - bindings-levmar-1.1.0.5
#  - levmar-1.2.1.8 -- Does not support base 4.9 at the moment. A more up to date fork is used
  - github: PHPirates/levmar
    commit: f36ef9ae1c0d44950a28a445d4f459257f77dd4d

# BLAS and LAPACK linear algebra C libraries required by levmar, from https://icl.cs.utk.edu/lapack-for-windows/lapack/#libraries_mingw
extra-include-dirs: [lib/]
extra-lib-dirs: [lib/]


Add levmar to build-depends in `.cabal` file

Now stack build should work, but ghci is broken:

ghc.EXE: Could not load `liblapack.dll'. Reason: addDLL: liblapack.dll or dependencies not loaded. (Win32 error 126)

ghc.EXE:  | C:\path\to\project\.stack-work\install\dbe016db\
lib\x86_64-windows-ghc-8.4.3\bindings-levmar-1.1.0.5-F0ngawY9GmwEQuOouY5SCO\HSbindings-levmar-1.1.0.5-F0ngawY9GmwEQuOouY5
SCO.o: unknown symbol `dgeqrf_'
ghc.EXE: unable to load package `bindings-levmar-1.1.0.5'

I tried:

Download https://sourceforge.net/projects/openblas/?source=typ_redirect
and put the dlls in C:\msys64\mingw64\bin and rename libgfortran-3.dll to libgfortran.dll

copy lib/ to C:\Windows\System32 and to mingw64\bin, add mingw64\bin to path