Use filename join to create nif loading path

src/esqlite3_nif.erl

@@ -35,11 +35,12 @@
 -on_load(init/0).
 
 init() ->
-    PrivDir = case code:priv_dir(esqlite) of
-        {error, bad_name} -> "./priv";
-        Dir -> Dir
+    NifName = "esqlite3_nif",
+    NifFileName = case code:priv_dir(esqlite) of
+        {error, bad_name} -> filename:join("priv", NifName);
+        Dir -> filename:join(Dir, NifName)
     end,
-    ok = erlang:load_nif(PrivDir ++ "/esqlite3_nif", 0).
+    ok = erlang:load_nif(NifFileName, 0).
 
 %% @doc Start a low level thread which will can handle sqlite3 calls. 
 %%