Oh, I figured it out (partly). There apparently is a po/POTFILES.in that
had to be updated, and it still contained references to the filebrowser/*
source files. I fixed that now, and "make distcheck" works. I also did
a "make update-po" in the po directory, and pushed the po/pot files to
Savannah master.
I can unpack the tar ball and build XBoard from it. After
./configure
make
sudo make install
it runs fine, except that it does not seem to be internationalized. It
has
the low buttons and line spacing, and "LANG=de_DE.utf8 xboard" does
not produce any translations. I have been in such a state before, and
it is probably just due to something I am doing wrong. I don't know what
brought me out of it last time (it was not a conscious action).