10075 make usr/src/tools smatch clean

*** 20,29 ****
--- 20,30 ----
  #
  #
  # Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  # Use is subject to license terms.
  #
+ # Copyright (c) 2018, Joyent, Inc.
  
  include ../../../Makefile.tools
  
  #
  # A `make install' from the tools directory needs to work, even if the rest of
*** 44,48 ****
--- 45,51 ----
          -I$(NATIVE_ADJUNCT)/include
  
  CPPFLAGS += $(HDRDIRS)
  CFLAGS += $(CCVERBOSE)
  CERRWARN += -_gcc=-Wno-parentheses
+ 
+ SMOFF += all_func_returns