I updated some packages on my Slackware system, including my X.org
packages. When I wanted to run startx again, I got the error:

fatal server error:
could not find font 'fixed'

I checked /var/log/Xorg.0.log , and saw lines like:

`fonts.dir' not found (or not valid) in "/usr/pkg/xorg/lib/X11/fonts/misc/".
`fonts.dir' not found (or not valid) in "/usr/pkg/xorg/lib/X11/fonts/100dpi/".

After running the command mkfontdir in every font directory, I was
able to start the Xserver again. Shouldn't this be done when the font
packages are being installed? I did get error message though when
installing them, like:

Updating font databases in the following directories:

        /usr/pkg/xorg/lib/X11/fonts/cyrillic (x11)
opendir: No such file or directory