Allow ejabberd to be compatible as a dependency for an Erlang project using rebar3

configure.ac

@@ -67,8 +67,7 @@ fi
 AC_PREFIX_DEFAULT(/usr/local)
 
 AC_CONFIG_FILES([Makefile
-		 vars.config
-		 src/ejabberd.app.src])
+		 vars.config])
 
 AC_ARG_ENABLE(all,
 [AC_HELP_STRING([--enable-all], [same as --enable-odbc --enable-mysql --enable-pgsql --enable-sqlite --enable-pam --enable-zlib --enable-redis --enable-elixir --enable-stun --enable-sip --enable-debug --enable-tools (useful for Dialyzer checks, default: no)])],

src/ejabberd.app.src.in

@@ -1,17 +0,0 @@
-%% $Id$
-
-{application, ejabberd,
- [{description, "@PACKAGE_NAME@"},
-  {vsn, "@PACKAGE_VERSION@"},
-  {modules, []},
-  {registered, []},
-  {applications, [kernel, stdlib, sasl, ssl]},
-  {included_applications, [os_mon, lager, mnesia, inets, p1_utils, fast_yaml, fast_tls, pkix, xmpp, cache_tab, eimp]},
-  {env, [{enabled_backends, [@enabled_backends@]}]},
-  {mod, {ejabberd_app, []}}]}.
-
-
-%% Local Variables:
-%% mode: erlang
-%% End:
-%% vim: set filetype=erlang tabstop=8:

src/ejabberd.app.src.script

@@ -0,0 +1,41 @@
+%% $Id$
+Vars = case file:consult(filename:join([filename:dirname(SCRIPT), "..", "vars.config"])) of
+    {ok, Terms} ->
+        Terms;
+    _Err ->
+        []
+    end,
+
+Env = case lists:keyfind(enabled_backends, 1, Vars) of
+    false ->
+        {env, []};
+    Backends ->
+        {env, [Backends]}
+    end,
+
+{application, ejabberd,
+ [{description, "ejabberd"},
+  lists:keyfind(vsn, 1, Vars),
+  {modules, []},
+  {registered, []},
+  {applications, [kernel, stdlib, sasl, ssl]},
+  {included_applications,
+    [os_mon,
+     lager,
+     mnesia,
+     inets,
+     p1_utils,
+     fast_yaml,
+     fast_tls,
+     pkix,
+     xmpp,
+     cache_tab,
+     eimp]},
+  Env,
+  {mod, {ejabberd_app, []}}]}.
+
+
+%% Local Variables:
+%% mode: erlang
+%% End:
+%% vim: set filetype=erlang tabstop=8:

vars.config.in

@@ -45,6 +45,8 @@
 {vsn, "@PACKAGE_VERSION@"}.
 
 %% Variables for overlay template files
+{package_name, "@PACKAGE_NAME@"}.
+{enabled_backends, [@enabled_backends@]}.
 
 %% Platform-specific installation paths
 {release, true}.