xsetroot -solid black is a program/executable
Code:
$ ls -l $(which xsetroot)
-rwxr-xr-x 1 root wheel 15656 Mar 26 2010 /usr/X11R6/bin/xsetroot
So it is not an configuration option in a config file. It needs to be run/executed.
I use
startx, a shell script, which invokes
/etc/X11/xinit/xinitrc
Code:
$ ls -l $(which startx)
-rwxr-xr-x 1 root wheel 4517 Mar 26 2010 /usr/X11R6/bin/startx
$ ls -l /etc/X11/xinit/xinitrc
-rw-r--r-- 1 root wheel 1057 Jan 10 10:01 /etc/X11/xinit/xinitrc
I had to add the
xsetroot command to this
xinitrc script.
I never used
xdm, but the X11 directory in /etc has an
xdm directory
Code:
$ ls -l /etc/X11/
total 40
drwxr-xr-x 2 root wheel 1024 Apr 5 2010 app-defaults
drwxr-xr-x 2 root wheel 512 Apr 5 2010 fs
drwxr-xr-x 2 root wheel 512 Apr 5 2010 twm
drwxr-xr-x 3 root wheel 512 Apr 5 2010 xdm
drwxr-xr-x 2 root wheel 512 Apr 5 2010 xinit
drwxr-xr-x 11 root wheel 512 Mar 26 2010 xkb
-rw-r--r-- 1 root wheel 4477 Apr 9 2010 xorg.conf
drwxr-xr-x 2 root wheel 512 Apr 5 2010 xsm
You could have a look there