libstd: Switch off legacy modes in both core and std.

src/rt/rust_builtin.cpp

@@ -180,6 +180,11 @@ rand_new_seeded(rust_vec_box* seed) {
     return rctx;
 }
 
+extern "C" CDECL void *
+rand_new_seeded2(rust_vec_box** seed) {
+    return rand_new_seeded(*seed);
+}
+
 extern "C" CDECL size_t
 rand_next(randctx *rctx) {
     return isaac_rand(rctx);
@@ -371,6 +376,11 @@ rust_list_files(rust_str *path) {
   return vec;
 }
 
+extern "C" CDECL rust_vec_box*
+rust_list_files2(rust_str **path) {
+    return rust_list_files(*path);
+}
+
 extern "C" CDECL int
 rust_path_is_dir(char *path) {
     struct stat buf;