without the -b option, "xdm start" never finishes. Reproducible: Always Steps to Reproduce:
Created attachment 164565 [details, diff] startDM.patch
patching startDM.sh is not the solution, upstream needs to make gdm backward compatible. please also note that is _masked_ and in _overlay_ so you better work with upstream for this kind of bug (and pass by on irc before that if you don't feel so confortable, have a chat with us on #gentoo-desktop).
I think the issue was that startDM.sh is used for launching other desktop managers as well (xdm, kdm and so on), and as those don't take a -b argument, it'll break those. That's at least what I heard from remi or someone - for some clarification. Feel free to check if my recalling of this #gentoo-desktop chat is true
Upstream bug #550170 has a patch to restore the previous behaviour of forking unless run with --nodaemon. http://bugzilla.gnome.org/attachment.cgi?id=120573&action=view
don't you see we are CCed there already ? Thanks for not adding noise if not needed.
this has fixed in overlay since monday or so.