I've tried again on a different computer and I get the same error. I can fix the warning about "gettext domain not found" but I don't know how to make the scripts work.
Of course I've already run make.
And I'm working inside build/
IIUC if I've already run 'make' 'make -C scripts && make -C python' will be useless. What else should I try?
fede@debian:~/lilypond-git/build/Documentation$ make ISOLANG=it check-translation
ISOLANG=it /usr/bin/python /home/fede/lilypond-git/scripts/auxiliar/check_translation.py langdefs.py: warning: lilypond-doc gettext domain not found. fede@debian:~/lilypond-git/build/Documentation$ fede@debian:~/lilypond-git/build/Documentation$ make ISOLANG=it update-translation
ISOLANG=it /usr/bin/python /home/fede/lilypond-git/scripts/auxiliar/check_translation.py --update langdefs.py: warning: lilypond-doc gettext domain not found. fede@debian:~/lilypond-git/build/Documentation$ fede@debian:~/lilypond-git/build/Documentation$ make -C po out=www messages
ls: impossibile accedere a ../../Documentation/snippets/*.ly: No such file or directory make: Entering directory `/home/fede/lilypond-git/build/Documentation/po' /home/fede/lilypond-git/./Documentation/po/GNUmakefile:28: warning: overriding commands for target `po-update'
/home/fede/lilypond-git/stepmake/stepmake/podir-targets.make:14: warning: ignoring old commands for target `po-update' mkdir -p ./out-www touch ./out-www/dummy.dep echo '*' > ./out-www/.gitignore
make: Leaving directory `/home/fede/lilypond-git/build/Documentation/po' ls: impossibile accedere a ../../Documentation/snippets/*.ly: No such file or directory make: Entering directory `/home/fede/lilypond-git/build/Documentation/po'
/home/fede/lilypond-git/./Documentation/po/GNUmakefile:28: warning: overriding commands for target `po-update' /home/fede/lilypond-git/stepmake/stepmake/podir-targets.make:14: warning: ignoring old commands for target `po-update'
msgfmt -o out-www/cs.mo /home/fede/lilypond-git/Documentation/po/cs.po msgfmt -o out-www/de.mo /home/fede/lilypond-git/Documentation/po/de.po msgfmt -o out-www/es.mo /home/fede/lilypond-git/Documentation/po/es.po
msgfmt -o out-www/fr.mo /home/fede/lilypond-git/Documentation/po/fr.po msgfmt -o out-www/hu.mo /home/fede/lilypond-git/Documentation/po/hu.po msgfmt -o out-www/it.mo /home/fede/lilypond-git/Documentation/po/it.po
msgfmt -o out-www/ja.mo /home/fede/lilypond-git/Documentation/po/ja.po msgfmt -o out-www/nl.mo /home/fede/lilypond-git/Documentation/po/nl.po msgfmt -o out-www/zh.mo /home/fede/lilypond-git/Documentation/po/zh.po
for i in cs de es fr hu it ja nl zh; do \ mkdir -p ./out-www/$i/LC_MESSAGES; \ cp ./out-www/$i.mo ./out-www/$i/LC_MESSAGES/lilypond-doc.mo; \ done touch out-www/messages make: Leaving directory `/home/fede/lilypond-git/build/Documentation/po'
fede@debian:~/lilypond-git/build/Documentation$ fede@debian:~/lilypond-git/build/Documentation$ fede@debian:~/lilypond-git/build/Documentation$ fede@debian:~/lilypond-git/build/Documentation$ make ISOLANG=it update-translation
ISOLANG=it /usr/bin/python /home/fede/lilypond-git/scripts/auxiliar/check_translation.py --update fede@debian:~/lilypond-git/build/Documentation$ make ISOLANG=it check-translation ISOLANG=it /usr/bin/python /home/fede/lilypond-git/scripts/auxiliar/check_translation.py