code: def generate(env):
      
  
      if 'CC' not in env:
          env['CC'] = env.Detect(compilers) or compilers[0]
  
      cc.generate(env)
  
      if env['PLATFORM'] in ['cygwin', 'win32']:
          env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
      else:
          env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS -fPIC')
      # determine compiler version
      version = detect_version(env, env['CC'])
      if version:
          env['CCVERSION'] = version
docs: Add Builders and construction variables for gcc to an Environment.