[RP] race condition when tmpwm returns too fast

[Bernhard R. Link]

Ratpoison seems to have problems regaining control after an tmpwm if
that tmpwm exists to fast.  The problem was found by Bruce V Chiarelli
and reported to the Debian BTS as http://bugs.debian.org/478979.

I can only reproduce if I kill the window manager run via tmpwm
manually. Also ratpoison is not always in an unresponsive state,
I also get "ratpoison: There can be only ONE." messages sometimes.

My guess is that this is a timing problem. While ratpoison uses XSync
in cmd_tmpwm, that only syncs itself and does not make sure the X server
realizes the other window manager is gone already.

I guess a fix would need to either check first there is no other window
manager (which I don't know how to do) or to use a different X error
handler (or making the default behave differently based on some flag)
in that phase and repeat until no error happens.

Hochachtungsvoll,
        Bernhard R. Link