I have deleted 2.4.4 and built 2.5.27 on SuSE now, and you are
right: compilation went quite smoothly. But it is not much use,
because none of my old 2.4.x scores work. I used convert-ly, but I
still have several problems. One score doesn't compile, and the
other ones have one-line-staves instead of five-line ones (this
-at least- seems to be a bug of the unstable version because the
score on page 48 of the 2.5 Manual, pdf version, shows the same
phenomenon).
So, I think that I will wait for a new stable version,
because I am fed up with spending days on trying to get
things running.