FWIW, I removed the xulrunner-dev package and managed to get a successful 32-bit compile by supplying only --disable-ipc to configure. If you want more details as to why this is necessary, see the various bug reports and articles regarding building Firefox on various other operating systems and/or hardware architectures found by googling "'--disable-ipc' firefox ppc".
I'd be happy to test new releases on Debian/ppc when they come out but in the mean time I'll get back to trying a 64-bit build again. -Gary -- http://gnuzilla.gnu.org
