I suspect that a recent change in GNUmakefile.in (revision 1.186, see attached patch, extracted from CVS) has something to do with this:
bash $ ls out/share/lilypond current bash $ ls out/share/lilypond/current
2.7.33 elisp lilypond-force mf python scripts dvips fonts ly ps scm tex
The "2.7.33"-directory is supposed to be located under out/share/lilypond, and the "current" directory is supposed to be a link, not a directory. Right? Reverting to
GNUmakefile.in revision 1.185 seems to fix this, but I guess that there were a reason for the patch in the first place...