Upon further examination, defining GREET_USER_STATIC fixes this issue. (I added -DGREET_USER_STATIC to CFLAGS in debian/rules; this is not a good permanent solution, as xdm is simply useless without it.
In addition to this fix, DEF_XDM_CONFIG must be defined to reflect that the xdm config file is now located at /usr/X11/etc/xdm/xdm-config.
Without these changes, xdm will not allow login. If the priority of this bug should be raised to reflect this, please do so.
Upon further examination, defining GREET_USER_STATIC fixes this issue. (I added -DGREET_USER_STATIC to CFLAGS in debian/rules; this is not a good permanent solution, as xdm is simply useless without it.
In addition to this fix, DEF_XDM_CONFIG must be defined to reflect that the xdm config file is now located at /usr/X11/ etc/xdm/ xdm-config.
Without these changes, xdm will not allow login. If the priority of this bug should be raised to reflect this, please do so.