s := t.s
	for {
		t.tok = ScanToken(s.Scan())
		if t.tok != scanner.Comment {
			break
		}
		text := s.TokenText()
		t.line += strings.Count(text, "\n")
		if constraint.IsGoBuild(text) {
			t.tok = BuildComment
			break
		}
	}
	switch t.tok {
	case '\n':
		t.line++
	case '-':
		if s.Peek() == '>' {
			s.Next()
			t.tok = ARR
			return ARR
		}

pkg go/build, type Package struct, XTestEmbedPatterns []string
pkg go/build, type Package struct, XTestEmbedPatternPos map[string][]token.Position
pkg go/build/constraint, func IsGoBuild(string) bool
pkg go/build/constraint, func IsPlusBuild(string) bool
pkg go/build/constraint, func Parse(string) (Expr, error)
pkg go/build/constraint, func PlusBuildLines(Expr) ([]string, error)