The logic in prune_libtool_files is not perfect[1].
If you are updating ebuild for whatever reason and see `find` command to
punt .la files, and replace it with prune_libtool_files then you also
need to build the package (with "every" possible USE flag combination)
to see if --all argument is also needed.
To clarify:
Use `prune_libtool_files --all` instead of plain `prune_libtool_files`
if you don't test the package with the USE flags.
Not going to point anyone with a finger but the accident has already
happened couple of times in tree :P
[1] http://bugs.gentoo.org/421197
