suppress warnings

src/expand.c

@@ -146,6 +146,8 @@ expand(pic_state *pic, pic_value obj, struct syntactic_env *env)
     pic_error(pic, "unexpected value type");
     return pic_undef_value();	/* unreachable */
   }
+  /* logic falw (suppress warnings gcc will emit) */
+  abort();
 }
 
 pic_value