8411 Build should warn when linking against libraries outside proto area

@@ -20,10 +20,11 @@
 #
 #
 # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 # Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
 # Copyright (c) 2011, 2016 by Delphix. All rights reserved.
+# Copyright 2017 RackTop Systems.
 #
 
 LIBRARY= libzfs.a
 VERS= .1
 

@@ -75,10 +76,13 @@
 $(NOT_RELEASE_BUILD)CPPFLAGS += -DDEBUG
 
 # There's no lint library for zlib, so only include this when building
 $(DYNLIB) := LDLIBS +=  -lz
 
+# Allow zlib to be taken from outside the proto area.
+$(ADJUNCT_PROTO_NOT_SET)DYNFLAGS += $(ZASSERTDEFLIB)=libz.so
+
 LINTFLAGS +=    -erroff=E_STATIC_UNUSED
 LINTFLAGS64 +=  -erroff=E_STATIC_UNUSED
 
 SRCS=   $(OBJS_COMMON:%.o=$(SRCDIR)/%.c)        \
         $(OBJS_SHARED:%.o=$(SRC)/common/zfs/%.c)