8411 Build should warn when linking against libraries outside proto area

@@ -10,10 +10,11 @@
 #
 
 #
 # Copyright 2014 Garrett D'Amore <garrett@damore.org>
 # Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
+# Copyright 2017 RackTop Systems.
 #
 
 include         $(SRC)/cmd/Makefile.cmd
 include         $(SRC)/cmd/mandoc/Makefile.common
 

@@ -28,6 +29,9 @@
 clean:
                 $(RM) $(OBJS)
 
 install:        all $(ROOTPROG)
 
+# Allow zlib to be taken from outside the proto area.
+$(ADJUNCT_PROTO_NOT_SET)LDFLAGS += $(ZASSERTDEFLIB)=libz.so
+
 include         $(SRC)/cmd/Makefile.targ