I just tried to build it on ppc64el and it fails with the same mistake. The patch attached solves this problem.
- Bug#804736: libwfut: FTBFS: sigc++/object_slot.... Aaron M. Ucko
- Bug#804736: libwfut: FTBFS: sigc++/object_... Olek Wojnar
- Processed: Re: Bug#804736: libwfut: FTBFS:... Debian Bug Tracking System
- Bug#804736: marked as done (libwfut: FTBFS... Debian Bug Tracking System
- Bug#804736: libwfut: FTBFS: sigc++/object_... Olek Wojnar
- Bug#804736: libwfut: FTBFS: sigc++/obj... Breno Leitao
- Bug#804736: libwfut: FTBFS: sigc++... James Cowgill
- Bug#804736: libwfut: FTBFS: si... Breno Leitao
