Add xref target, with exclusions

rebar.config

@@ -5,5 +5,8 @@
             {git, "git://github.com/DeadZen/goldrush.git", {tag, "0.1.6"}}}
        ]}.
 
+{xref_checks, []}.
+{xref_queries, [{"(XC - UC) || (XU - X - B - lager_default_tracer : Mod)", []}]}.
+
 {cover_enabled, true}.
 {edoc_opts, [{stylesheet_file, "./priv/edoc.css"}]}.

tools.mk

@@ -4,6 +4,9 @@ test: compile
 docs:
 	./rebar doc skip_deps=true
 
+xref:
+	./rebar xref skip_deps=true
+
 PLT ?= $(HOME)/.riak_combo_dialyzer_plt
 LOCAL_PLT = .local_dialyzer_plt
 DIALYZER_FLAGS ?= -Wunmatched_returns