go:generate yaegi extract "XXX" not support custom tags

[Tudongye]

The following program sample.go triggers an unexpected result

// ~/hello/h.go

//go:build custom
// +build custom

package hello

func Hello() {
}

Expected result

$ cd ~/hello
$ yaegi extract h.go
$ ls
hello.go h.go

// if delete "go:build custom" "+build custom", i can get "hello.go" 
/*
 func init() {
        Symbols["hello/hello"].....
*/

Got

$ cd ~/hello
$ yaegi extract hello.go
no buildable Go source files in /home/hello

Yaegi Version

0.16.1

Additional Notes

func (e *Extractor) Extract( ...... pkg, err := importer.ForCompiler(token.NewFileSet(), "source", nil).Import(pkgIdent)
I think the problm lies here.
Compiler of "source" use the default buildcontext.
Its BuildTags always is "".
So my Go files that have build tag "custom" will be ignored by "Import".
I try "yaegi extract -tag=pb hello.go", but not useful.The "tag" is not the one I want