diff --git a/erlang/apps/ar/src/ar.erl b/erlang/apps/ar/src/ar.erl
index 11c091f..adb0a1c 100644
--- a/erlang/apps/ar/src/ar.erl
+++ b/erlang/apps/ar/src/ar.erl
@@ -22,7 +22,7 @@
 -export([main/1]).
 
 -include_lib("kernel/include/file.hrl").
--include_lib("ar/include/pdp10_ar.hrl").
+-include_lib("lib/include/pdp10_ar.hrl").
 -include_lib("lib/include/pdp10_elf36.hrl").
 
 %% in-core version of the ar header
diff --git a/erlang/apps/ar/include/pdp10_ar.hrl b/erlang/apps/lib/include/pdp10_ar.hrl
similarity index 100%
rename from erlang/apps/ar/include/pdp10_ar.hrl
rename to erlang/apps/lib/include/pdp10_ar.hrl