Gnome Core (seems to) require --with-window-manager

[Colin Scott <cs iinet com au>]

I recently (last 24 hours) changed WMs from fvwm2 to WindowMaker. I had
been compiling gnome-core with --with-window-manager=fvwm2, and I
noticed that when I changed (surprise), I got an error message becuase I
was not longer running fvwm2.

What does this flag actually do. I have since recompiled, but I'd like
to knwo if it's necessary to specify the --with-window-manager option.

Colin Scott