Comment 7 for bug 1323592

Here's a patch that performs a conditional build. I've dropped support for the now-obsolete libwpg-0.1, but it should work with everything since then.

I've tested it on Ubuntu Trusty (libwpg-0.2 etc), but I don't have a build system with librevenge handy, so I can't promise it'll work! Please feel free to test :)