Lots more work on eng::malloc

luprex/core/cpp/luastack.cpp

@@ -34,11 +34,21 @@ static int panicf(lua_State *L) {
     exit(1);
 }
 
+// An allocator for lua states that uses system malloc and system free.
+static void *l_alloc(void *ud, void *ptr, size_t osize, size_t nsize) {
+    if (nsize == 0) {
+        free(ptr);
+        return NULL;
+    } else {
+        return realloc(ptr, nsize);
+    }
+}
 
 lua_State *LuaStack::newstate (lua_Alloc allocf) {
-  lua_State *L = lua_newstate(allocf, NULL);
-  if (L) lua_atpanic(L, &panicf);
-  return L;
+    if (allocf == nullptr) allocf = l_alloc;
+    lua_State *L = lua_newstate(allocf, NULL);
+    if (L) lua_atpanic(L, &panicf);
+    return L;
 }
 
 bool LuaStack::ckboolean(LuaSlot s) const {