Blacklist the following files from version control:

* prism/lib/prism.jar: this is generated by the "binary" target in
  prism/Makefile.
* prism/lib/prism-sources.jar: this is generated by the "source-jar"
  target in prism/Makefile.
* prism/prism-sources.txt: this is a temporary build file generated by
  the "source-jar" target in prism/Makefile and will be deleted if it
  succeeds, but will be left behind if jar(1) exits unsuccessfully.