Hello Guix!

The packages in linphone.scm has been severely outdated and posses risk, 
as upstream even removed the tarballs. So I have re-worked all the 
packages in linphone.scm, as fast as I could.

@Maxim: Thanks so much for offering to review.

Please find the attached patch-set.

I am still working on one component, linphone-desktop. The upgrade from 
v4.1.1 to v4.2.5, turns to be more complicated than I expected.

Regards,
RG.