stable build from source

Hi,

I am trying to compile the "stable" version on a Ubuntu 20.04 machine.
This is what I have to report:

The message was:

Download failed or wrong checksum of package libbiosig!
------------------------------------------------------------
Platz: http://agora.octave.org/mxe-pkg-src/biosig-2.0.4.src.tar.gz [folgend]
--2020-07-08 11:29:58--
http://agora.octave.org/mxe-pkg-src/biosig-2.0.4.src.tar.gz
Auflösen des Hostnamens agora.octave.org (agora.octave.org) ...
162.243.101.184
Verbindungsaufbau zu agora.octave.org (agora.octave.org)|162.243.101.184|:80
... verbunden.
HTTP-Anforderung gesendet, auf Antwort wird gewartet ... 404 Not Found
2020-07-08 11:29:58 FEHLER 404: Not Found.
Download failed!
------------------------------------------------------------

I manually downloaded and copied the pkg-archive file
"biosig-2.0.4.src.tar.gz"
into the folder specified by means of switch "--with-pkg-dir", but this was
not helpful.

Regards,

Stefan