I'm 99% sure that what happened is that the kdenlive developers use
unsermake themselves, and forgot to re-run make -f Makefile.cvs when
making the distribution tarball for release.
The files generated for unsermake are not compatible with automake. The
choice of unsermake and automake happens before the configure script is
created in the KDE 3 build system (when running make -f Makefile.cvs,
which is the same as make -f admin/Makefile.common cvs).