The default installation settings of xdm match those used for most platforms in the previous X.Org releases:
Scripts & modules: $(libdir)/X11/xdm (aka $(prefix)/lib/X11/xdm)
Configuration files: $(libdir)/X11/xdm
Pixmap files: $(libdir)/X11/xdm/pixmaps
Log files: /var/log
Process id/lock files: /var/run
xauth cookie files: /var/lib/xdm
These may be overridden with the following options to configure:
Loadable modules: --with-xdmlibdir
Scripts: --with-xdmscriptdir (or --with-xdmlibdir)
Configuration files: --with-xdmconfigdir (or --with-xdmlibdir)
Pixmap files: --with-xdmpixmapdir (or --with-xdmlibdir)
Log files: --with-logdir
Process id/lock files: --with-piddir
xauth cookie files: --with-authdir
For instance, some packagers/sites may prefer:
--with-xdmconfigdir=/etc/X11/xdm
--with-xdmlibdir=$(prefix)/lib/xdm
--with-xdmscriptdir=/etc/X11/xdm
The handling of --with-utmp-file & --with-wtmp-file have also changed slightly since previous versions of xdm:
--with-{u,w}tmp-file
[default] write records to utmp/wtmp files, but allow sessreg to
use its builtin default paths. Omits -u/-w flag entirely from
sessreg command in Xstartup & Xreset files.
--with-{u,w}tmp-file=<filename>
write records to utmp/wtmp files at specified filename.
Passes filename as argument to sessreg -u/-w flag in Xstartup/Xreset.
--without-{u,w}tmp-file or --with-{u,w}tmp-file=none
Do not write records to utmp/wtmp files at all.
Passes "none" as argument to sessreg -u/-w flag in Xstartup/Xreset.
All questions regarding this software should be directed at the Xorg mailing list:
https://lists.x.org/mailman/listinfo/xorg
The master development code repository can be found at:
https://gitlab.freedesktop.org/xorg/app/xdm
Please submit bug reports and requests to merge patches there.
For patch submission instructions, see:
https://www.x.org/wiki/Development/Documentation/SubmittingPatches