Fix Windows-specific definition
diff --git a/rebar.config b/rebar.config
index 202a563..43e2924 100644
--- a/rebar.config
+++ b/rebar.config
@@ -1 +1,2 @@
+{erl_opts, [{platform_define, "win32", 'WINDOWS'}]}.
 {eunit_compile_opts, [{platform_define, "win32", 'WINDOWS'}]}.