Flush debug outputs

os2.rkt

@@ -445,6 +445,7 @@
 		 [processes (hash-set (vm-processes state) new-pid initial-process)]
 		 [next-process-id (+ new-pid 1)]))
   (printf "~a PID ~v (~a) started~n" (vm-name state) new-pid new-name)
+  (flush-output (current-output-port))
   (run-trapk spawned-state spawning-pid k new-pid))
 
 (define (print-kill vm-name pid-to-kill process-name reason)
@@ -464,7 +465,8 @@
 		 vm-name
 		 pid-to-kill
 		 process-name
-		 reason)]))
+		 reason)])
+  (flush-output (current-output-port)))
 
 (define (do-kill pid-to-kill reason state)
   (cond