inkscape changed how to identify export file.

Now it is
%.pdf : %.svg
inkscape --export-pdf=$@ $<

%.eps : %.svg
inkscape --export-eps=$@ $<

It should be now:

%.pdf : %.svg
inkscape --export-type=pdf --export-filename=$@ $<

%.eps : %.svg
inkscape --export-type=eps --export-filename=$@ $<