11422 ztest needs smatch flag

*** 20,30 ****
  #
  #
  # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  # Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  # Copyright 2017 RackTop Systems.
! # Copyright 2019, Joyent, Inc.
  
  PROG= ztest
  OBJS= $(PROG).o
  SRCS= $(OBJS:%.o=../%.c)
  
--- 20,30 ----
  #
  #
  # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  # Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  # Copyright 2017 RackTop Systems.
! # Copyright 2019 Joyent, Inc.
  
  PROG= ztest
  OBJS= $(PROG).o
  SRCS= $(OBJS:%.o=../%.c)
  
*** 58,67 ****
--- 58,70 ----
  CERRWARN += -_gcc=-Wno-switch
  
  # false positive
  SMOFF += signed
  
+ # needs work
+ SMOFF += all_func_returns
+ 
  .KEEP_STATE:
  
  all: $(PROG)
  
  $(PROG): $(OBJS)