// arbitrary file sizes, filenames of arbitrary encoding and length,
	// sparse files, and other features.
	//
	// It is recommended that PAX be chosen over GNU unless the target
	// application can only parse GNU formatted archives.
	//
	// Reference:
	//	https://www.gnu.org/software/tar/manual/html_node/Standard.html
	FormatGNU

	// Schily's tar format, which is incompatible with USTAR.

		check(err)
		pcert, err := x509.ParseCertificate(cert)
		check(err)
		fmt.Printf("export GOIOS_DEV_ID=\"%s\"\n", pcert.Subject.CommonName)

		appID, err := plistExtract(fname, "Entitlements:application-identifier")
		check(err)
		fmt.Printf("export GOIOS_APP_ID=%s\n", appID)

		teamID, err := plistExtract(fname, "Entitlements:com.apple.developer.team-identifier")
		check(err)

	return &Arena{a: runtime_arena_newArena()}
}

// Free frees the arena (and all objects allocated from the arena) so that
// memory backing the arena can be reused fairly quickly without garbage
// collection overhead. Applications must not call any method on this
// arena after it has been freed.
func (a *Arena) Free() {
	runtime_arena_arena_Free(a.a)
	a.a = nil
}

// New creates a new *T in the provided arena. The *T must not be used after