Note: this is a temporary workaround until the source of the crashes
on SMP machines is found.  It may cause minor resource leakage in some
unusual apps, but the alternative - at present - is random crashes.
The problem has been reported upstream, and a better fix is expected
before long.

--- tcl8.4-8.4.7.orig/unix/tclUnixNotfy.c
+++ tcl8.4-8.4.7/unix/tclUnixNotfy.c
@@ -1031,7 +1031,5 @@
     triggerPipe = -1;
     Tcl_ConditionNotify(&notifierCV);
     Tcl_MutexUnlock(&notifierMutex);
-
-    TclpThreadExit (0);
 }
 #endif
