Use compilation flags used during build to compile modules in ext_mod

This fixes issue #3178

mix.exs

@@ -51,12 +51,25 @@ defmodule Ejabberd.Mixfile do
     end
   end
 
+  defp if_version_below(ver, okResult) do
+    if :erlang.system_info(:otp_release) < ver do
+      okResult
+    else
+      []
+    end
+  end
+
   defp erlc_options do
     # Use our own includes + includes from all dependencies
     includes = ["include"] ++ deps_include(["fast_xml", "xmpp", "p1_utils"])
-    [:debug_info, {:d, :ELIXIR_ENABLED}] ++ cond_options() ++ Enum.map(includes, fn(path) -> {:i, path} end) ++
+    result = [:debug_info, {:d, :ELIXIR_ENABLED}] ++
+             cond_options() ++
+             Enum.map(includes, fn (path) -> {:i, path} end) ++
              if_version_above('20', [{:d, :DEPRECATED_GET_STACKTRACE}]) ++
+             if_version_below('22', [{:d, :LAGER}]) ++
              if_function_exported(:erl_error, :format_exception, 6, [{:d, :HAVE_ERL_ERROR}])
+    defines = for {:d, value} <- result, do: {:d, value}
+    result ++ [{:d, :ALL_DEFS, defines}]
   end
 
   defp cond_options do

rebar.config.script

@@ -304,12 +304,14 @@ fun(Hooks) ->
 end,
 
 ProcessErlOpt = fun(Vals) ->
-			lists:map(
+			R = lists:map(
 			  fun({i, Path}) ->
 				  {i, ResolveDepPath(Path)};
 			     (ErlOpt) ->
 				  ErlOpt
-			  end, Vals)
+			  end, Vals),
+			M = lists:filter(fun({d, M}) -> true; (_) -> false end, R),
+			[{d, 'ALL_DEFS', M} | R]
 		end,
 
 ProcssXrefExclusions = fun(Items) ->

src/ext_mod.erl

@@ -570,7 +570,7 @@ compile_result(Results) ->
     end.
 
 compile_options() ->
-    [verbose, report_errors, report_warnings]
+    [verbose, report_errors, report_warnings, ?ALL_DEFS]
     ++ [{i, filename:join(app_dir(App), "include")}
         || App <- [fast_xml, xmpp, p1_utils, ejabberd]]
     ++ [{i, filename:join(mod_dir(Mod), "include")}