diff --git a/Makefile b/Makefile
index 04d1de1..1022b4b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,2 +1,9 @@
-all:
+all: include/tz_index.hrl
 	./rebar compile
+
+check:
+	./rebar eunit
+
+include/tz_index.hrl: src/ibuild.erl include/tz_database.hrl
+	cd include && ln -s ../src/ibuild.erl && escript ibuild.erl; EV=$$?; rm ibuild.erl; exit $$EV
+
diff --git a/src/ibuild.erl b/src/ibuild.erl
old mode 100644
new mode 100755
index ab1f1fa..3334c1d
--- a/src/ibuild.erl
+++ b/src/ibuild.erl
@@ -1,6 +1,6 @@
 -module(ibuild).
 
--export([build_index/0]).
+-export([build_index/0, main/1]).
 
 -include("tz_database.hrl").
 
@@ -22,3 +22,7 @@ build_index() ->
    I = lists:foldl(F, dict:new(), ?tz_database),
    {ok, File} = file:open("tz_index.hrl", [write]),
    io:fwrite(File, "-define(tz_index, ~p).", [I]).
+
+%% So this can be run from escript:
+main(_Args) ->
+   build_index().