I encountered this bug when I decided to use 'stty tostop'
on my console window.  I get warning messages printed to my
console whenever I start X to the effect that fvwm wasn't
found and that it's resorting to twm to get me going.  (I
have yet to care about that, since I like twm fine enough.)
It turns out that this message apparently causes xinit to
hang when starting in a console with tostop set.

I'll mail my patch to startx to turn off tostop before and
restore the original stty settings after xinit runs.