I had a look at this issue, and the cause is in src/Makefile.am, which intentionally list several files both in both dfarc_SOURCES and BUILT_SOURCES. The problematic files are generated but stored in the tarball to save a build dependencuy (wxglade).
I am not sure how to avoid this problem, and left it to someone with more time to spend on it. :) -- Happy hacking Petter Reinholdtsen
