Add --enable-system-deps configure option

configure.ac

@@ -212,6 +212,14 @@ AC_ARG_ENABLE(latest_deps,
   *) AC_MSG_ERROR(bad value ${enableval} for --enable-latest-deps) ;;
 esac],[if test "x$latest_deps" = "x"; then latest_deps=false; fi])
 
+AC_ARG_ENABLE(system_deps,
+[AC_HELP_STRING([--enable-system-deps], [makes rebar use localy installed dependences instead of downloading them (default: no)])],
+[case "${enableval}" in
+  yes) system_deps=true ;;
+  no)  system_deps=false ;;
+  *) AC_MSG_ERROR(bad value ${enableval} for --enable-system-deps) ;;
+esac],[if test "x$system_deps" = "x"; then system_deps=false; fi])
+
 AC_ARG_ENABLE(stun,
 [AC_HELP_STRING([--enable-stun], [enable STUN/TURN support (default: no)])],
 [case "${enableval}" in
@@ -274,6 +282,7 @@ AC_SUBST(sip)
 AC_SUBST(debug)
 AC_SUBST(tools)
 AC_SUBST(latest_deps)
+AC_SUBST(system_deps)
 AC_SUBST(CFLAGS)
 AC_SUBST(CPPFLAGS)
 AC_SUBST(LDFLAGS)

rebar.config.script

@@ -23,10 +23,12 @@ Vars = case file:consult(filename:join([filename:dirname(SCRIPT),"vars.config"])
 	       Terms;
 	   _Err ->
 	       []
-       end ++ [{cflags, "-g -O2 -Wall"}, {cppflags, "-g -O2 -Wall"}, {ldflags, ""}],
+       end ++ [{cflags, "-g -O2 -Wall"}, {cppflags, "-g -O2 -Wall"},
+	       {ldflags, ""}, {system_deps, false}],
 {cflags, CFlags} = lists:keyfind(cflags, 1, Vars),
 {cppflags, CPPFlags} = lists:keyfind(cppflags, 1, Vars),
 {ldflags, LDFlags} = lists:keyfind(ldflags, 1, Vars),
+{system_deps, SystemDeps}  = lists:keyfind(system_deps, 1, Vars),
 
 GetCfg0 = fun(F, Cfg, [Key | Tail], Default) ->
 		  Val = case lists:keyfind(Key, 1, Cfg) of
@@ -336,7 +338,7 @@ Rules = [
 	  ProcessFloatingDeps, [], []},
 	 {[deps], IsRebar3,
 	  Rebar3DepsFilter, []},
-	 {[deps], os:getenv("USE_GLOBAL_DEPS") /= false,
+	 {[deps], SystemDeps /= false,
 	  GlobalDepsFilter, []}
 	],
 

vars.config.in

@@ -60,6 +60,7 @@
 {docdir, "{{release_dir}}/doc"}.
 
 {latest_deps, @latest_deps@}.
+{system_deps, @system_deps@}.
 
 {ldflags, "@LDFLAGS@"}.
 {cflags, "@CFLAGS@"}.