Issues installing slycot via pip #155

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_C:\Windows\system32>pip install slycot
Collecting slycot
  Using cached slycot-0.4.0.0.tar.gz (1.5 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Requirement already satisfied: numpy in c:\users\psc\appdata\local\programs\python\python39\lib\site-packages (from slycot) (1.20.3)
Building wheels for collected packages: slycot
  Building wheel for slycot (PEP 517) ... error
  ERROR: Command errored out with exit status 1:
   command: 'c:\users\psc\appdata\local\programs\python\python39\python.exe' 'c:\users\psc\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\pep517\in_process\_in_process.py' build_wheel 'C:\Users\psc\AppData\Local\Temp\tmp_pm1h_ju'
       cwd: C:\Users\psc\AppData\Local\Temp\pip-install-g41g7ty1\slycot_37cc017271c84d17ac02eef4e57cb82e
  Complete output (56 lines):
  Not searching for unused variables given on the command line.
  -- The C compiler identification is unknown
  CMake Error at CMakeLists.txt:3 (ENABLE_LANGUAGE):
    The CMAKE_C_COMPILER:

      cl

    is not a full path and was not found in the PATH.

    To use the NMake generator with Visual C++, cmake must be run from a shell
    that can use the compiler cl from the command line.  This environment is
    unable to invoke the cl compiler.  To fix this problem, run cmake from the
    Visual Studio Command Prompt (vcvarsall.bat).

    Tell CMake where to find the compiler by setting either the environment
    variable "CC" or the CMake cache entry CMAKE_C_COMPILER to the full path to
    the compiler, or to the compiler name if it is in the PATH.


  -- Configuring incomplete, errors occurred!
  See also "C:/Users/psc/AppData/Local/Temp/pip-install-g41g7ty1/slycot_37cc017271c84d17ac02eef4e57cb82e/_cmake_test_compile/build/CMakeFiles/CMakeOutput.log".
  See also "C:/Users/psc/AppData/Local/Temp/pip-install-g41g7ty1/slycot_37cc017271c84d17ac02eef4e57cb82e/_cmake_test_compile/build/CMakeFiles/CMakeError.log".
  FC ('-DCMAKE_Fortran_COMPILER=', 'c:/users/psc/appdata/local/programs/python/python39/Library/bin/flang.exe')
  F2PY ('-DF2PY_EXECUTABLE=', 'c:/users/psc/appdata/local/programs/python/python39/Scripts/f2py.exe')
  NUMPY_INCLUDE ('-DNumPy_INCLUDE_DIR=', 'c:/users/psc/appdata/local/programs/python/python39/Include')
  ['-DSLYCOT_VERSION:STRING=0.4.0', '-DGIT_REVISION:STRING=ac0944b363a6cfcc0c3d5128cdd484d74173aa3b', '-DISRELEASE:STRING=True', '-DFULL_VERSION=0.4.0.gitac0944b', '-GNMake Makefiles', '-DCMAKE_Fortran_COMPILER=c:/users/psc/appdata/local/programs/python/python39/Library/bin/flang.exe', '-DF2PY_EXECUTABLE=c:/users/psc/appdata/local/programs/python/python39/Scripts/f2py.exe', '-DNumPy_INCLUDE_DIR=c:/users/psc/appdata/local/programs/python/python39/Include', '-DCMAKE_Fortran_SIMULATE_VERSION=5.0.0', '-DCMAKE_Fortran_COMPILER_ID=Flang', '-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON']


  --------------------------------------------------------------------------------
  -- Trying "NMake Makefiles (Visual Studio 15 2017 Win64 v141)" generator
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  --
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  -- Trying "NMake Makefiles (Visual Studio 15 2017 Win64 v141)" generator - failure
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  ********************************************************************************
  scikit-build could not get a working generator for your system. Aborting build.

  Building windows wheels for Python 3.9 requires Microsoft Visual Studio 2017.
  Get it with "Visual Studio 2017":

    https://visualstudio.microsoft.com/vs/

  ********************************************************************************
  ----------------------------------------
  ERROR: Failed building wheel for slycot
Failed to build slycot
ERROR: Could not build wheels for slycot which use PEP 517 and cannot be installed directly_
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