execute_cmd.c assumes that the value in time_t shell_start_time is in ticks, as how one would get it from a call to the times() function. But for some reason, shell.c puts seconds in it, rather than ticks.
Moreover, execute_cmd.c uses times() as a fallbask for !defined (HAVE_GETTIMEOFDAY), yet shell.c uses a call to gettimeofday() to put those seconds in shell_start_time. In execute_cmd.c this bug breaks things in "if (posixly_correct && nullcmd)". -- Pourko
