code: def generate(env):
      
      path, _f77, _shf77, version = get_xlf77(env)
      if path:
          _f77 = os.path.join(path, _f77)
          _shf77 = os.path.join(path, _shf77)
  
      f77.generate(env)
  
      env['F77'] = _f77
      env['SHF77'] = _shf77
docs: Add Builders and construction variables for the Visual Age FORTRAN
      compiler to an Environment.