fix: add upgrade/recompile support

Author: polvalente

c_src/emlx_nif.cpp

@@ -804,6 +804,16 @@ static int load(ErlNifEnv *env, void **priv_data, ERL_NIF_TERM load_info) {
   return 0;
 }
 
+int upgrade(ErlNifEnv *env, void **priv_data, void **old_priv_data, ERL_NIF_TERM load_info) {
+  // Silence "unused var" warnings.
+  (void)(env);
+  (void)(priv_data);
+  (void)(old_priv_data);
+  (void)(load_info);
+
+  return 0;
+}
+
 UNARY_OP(abs)
 UNARY_OP(ceil)
 UNARY_OP(conjugate)
@@ -1147,4 +1157,4 @@ static ErlNifFunc nif_funcs[] = {
     {"call_compiled", 2, call_compiled, ERL_NIF_DIRTY_JOB_CPU_BOUND}};
 
 // Update the NIF initialization
-ERL_NIF_INIT(Elixir.EMLX.NIF, nif_funcs, load, NULL, NULL, NULL)
+ERL_NIF_INIT(Elixir.EMLX.NIF, nif_funcs, load, NULL, upgrade, NULL)