Release notes of xiphos state that since 2.4 it should build against Firefox 3.0 / Xulrunner 1.9.0: RELEASE-NOTES:2084401 Problem compiling with xul-1.9/firefox 3 on Debian/Gentoo Can you please check and adapt dependencies so no old firefox/xulrunner versions are pulled in? Also, please check whether it can build against Firefox 3.5 or Xulrunner 1.9.1 if possible to be prepared for the future.
Fixed in 3.1.2