8411 Build should warn when linking against libraries outside proto area

*** 23,32 ****
--- 23,33 ----
  # Use is subject to license terms.
  #
  
  #
  # Copyright (c) 2012 by Delphix. All rights reserved.
+ # Copyright 2017 RackTop Systems.
  #
  
  PROG = isns
  
  DSRC = isns_provider.d
*** 68,77 ****
--- 69,81 ----
  obj.o := CERRWARN += -erroff=E_CONST_OBJ_SHOULD_HAVE_INITIZR
  obj.o := CERRWARN += -erroff=E_IMPLICIT_DECL_FUNC_RETURN_INT
  
  LDLIBS          += -lsecdb -lsocket -lnsl -lscf -lxml2
  
+ # Allow libxml2 to be taken from outside the proto area.
+ $(ADJUNCT_PROTO_NOT_SET)LDFLAGS += $(ZASSERTDEFLIB)=libxml2.so
+ 
  .KEEP_STATE:
  
  all:    $(PROG)
  
  $(PROG): $(OBJS)