That was it, intltool-prepare.
I put this line into build_all_from_scratch.sh (see hello-world example), and voila, no questions at all. Apparently I was right not compiling liber*** libraries but using only their headers. Thank you!
BTW, commenting out the two mentioned lines in filemodel.c helps, now the labels for .desktop files are back to the expected ones
I attach the binary compiled for dr800s.