Replace BM_DEBUG_SUPPORT with XDT_FEATURE_DEBUG in configure.in.in, otherwise when managing the package with xfce4-dev-tools-4.10.0 the ./configure switch for debug will vanish.
Thanks for reporting this. commit b064ec31b3733c0ca4cf6f7407292340eef531f7 Author: David Mohr <david@mcbf.net> Date: Sat Jul 7 18:10:25 2012 -0600 Replace BM_DEBUG_SUPPORT with XDT_FEATURE_DEBUG