code: func (c *Checker) processCgoExported(pkg *lint.Pkg, node ast.Node) {
  	if node, ok := node.(*ast.FuncDecl); ok {
  		if node.Doc == nil {
  			return
  		}
  		for _, cmt := range node.Doc.List {
  			if !strings.HasPrefix(cmt.Text, "//go:cgo_export_") {
  				return
  			}
  			obj := pkg.TypesInfo.ObjectOf(node.Name)
  			c.graph.roots = append(c.graph.roots, c.graph.getNode(obj))
  		}
  	}
  }
docs: // processCgoExported marks functions as used if they're being
  // exported to cgo.