Upstream maintainer Marco Pessotto has written me an e-mail informing me that he tagged a new version of pov-mode for emacs. It should get rid of a number of compiler warnings, and also includes some other small improvements. Perhaps https://gitorious.org/pov-mode/pov-mode/archive-tarball/v3.3 will make a suitable SRC_URI for this package. Apparently that file was generated once, so I assume that it won't change in the future, thus resulting in fixed checksums.
Thank you.