Update to latest master branch of immer (#438)

* update immer submodule

* point immer submodule at our fork for now

* update llvm backend runtime to work with new API of immer

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "deps/immer"]
 	path = deps/immer
-	url = https://github.com/arximboldi/immer.git
+	url = https://github.com/runtimeverification/immer.git
 [submodule "deps/rapidjson"]
 	path = deps/rapidjson
 	url = https://github.com/Tencent/rapidjson

include/runtime/header.h

@@ -156,7 +156,8 @@ struct KEq {
 
 using list = immer::flex_vector<
     KElem, immer::memory_policy<
-               immer::heap_policy<kore_alloc_heap>, immer::no_refcount_policy>>;
+               immer::heap_policy<kore_alloc_heap>, immer::no_refcount_policy,
+               immer::no_lock_policy>>;
 using map = immer::map<
     KElem, KElem, HashBlock, std::equal_to<KElem>, list::memory_policy>;
 using set

runtime/collect/migrate_roots.cpp

@@ -12,12 +12,14 @@ extern "C" {
 void migrate(block **blockPtr);
 
 void migrateRoots() {
-  auto &l = list_impl::empty();
-  migrate_list((void *)&l);
+  auto &l1 = list_impl::empty_root();
+  migrate_collection_node((void **)&l1);
+  auto &l2 = list_impl::empty_tail();
+  migrate_collection_node((void **)&l2);
   auto &s = set_impl::empty();
-  migrate_set((void *)&s);
+  migrate_collection_node((void **)&s);
   auto &m = map_impl::empty();
-  migrate_map((void *)&m);
+  migrate_collection_node((void **)&m);
   if (kllvm_randStateInitialized) {
     auto &rand = kllvm_randState->_mp_seed->_mp_d;
     string *limbs = struct_base(string, data, rand);