Revert so path resolution.

Makefile

@@ -11,5 +11,5 @@ tests:
 clean:
 	@rebar3 clean
 
-hex-publish: distclean
+hex-publish: clean
 	rebar3 hex publish

rebar.config

@@ -4,8 +4,6 @@
             {w, all},
             warn_export_all]}.
 
-{deps, [{hex2bin, "1.0.0"}]}.
-
 {plugins, [pc]}.
 
 {provider_hooks, [

src/crc32cer.app.src

@@ -7,10 +7,10 @@
   , {env,[]}
   , {modules,[]}
   , {licenses,["Apache License 2.0"]}
-  , {links,[{"Github","https://github.com/zmstone/crc32cert .git"}]}
-  , {build_tools,["make","rebar","rebar3"]}
-  , {files,["c_src/*.h","c_src/*.c", "rebar.config",
-            "src", "erlang.mk","Makefile"]}
+  , {links,[{"Github","https://github.com/zmstone/crc32cer.git"}]}
+  , {build_tools,["rebar3"]}
+  , {files,["c_src/Makefile", "c_src/*.h","c_src/*.c", "rebar.config",
+            "src", "Makefile"]}
   ]
 }.
 

src/crc32cer.erl

@@ -5,10 +5,6 @@
 
 -on_load(init/0).
 
--ifndef(APPLICATION).
--define(APPLICATION, crc32cer).
--endif.
-
 -spec init() -> ok.
 init() ->
   _ = erlang:load_nif(so_path(), 0),
@@ -24,15 +20,24 @@ nif(_Acc, _IoData) ->
 
 -spec so_path() -> string().
 so_path() ->
-  filename:join(case code:priv_dir(?MODULE) of
-                  {error, bad_name} ->
-                    %% this is here for testing purposes
-                    filename:join(
-                      [filename:dirname(
-                         code:which(?MODULE)),"..","priv"]);
-                  Dir ->
-                    Dir
-                end, atom_to_list(?MODULE) ++ "_nif").
+  filename:join([get_nif_bin_dir(), "crc32cer_nif"]).
+
+get_nif_bin_dir() ->
+  {ok, Cwd} = file:get_cwd(),
+  get_nif_bin_dir(
+    [ code:priv_dir(crc32cer)
+    , filename:join([Cwd, "..", "priv"])
+    , filename:join(Cwd, "priv")
+    , os:getenv("NIF_BIN_DIR")
+    ]).
+
+get_nif_bin_dir([]) -> erlang:error(crc32cer_nif_not_found);
+get_nif_bin_dir([false | Rest]) -> get_nif_bin_dir(Rest);
+get_nif_bin_dir([Dir | Rest]) ->
+  case filelib:wildcard(filename:join([Dir, "crc32cer_nif*"])) of
+    [] -> get_nif_bin_dir(Rest);
+    [_ | _] -> Dir
+  end.
 
 -ifdef(TEST).