Comment 1 for bug 1815277

I managed to fix 1 of 2 memory leaks in the attached branch: The remaining leak:

Direct leak of 128 byte(s) in 4 object(s) allocated from:
    #0 0x7f7c3fdd2f40 in realloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdef40)
    #1 0x5617582dba7b in l_alloc ../src/third_party/eris/lauxlib.c:1015
    #2 0x5617582e8cb2 in luaM_realloc_ ../src/third_party/eris/lmem.c:86
    #3 0x5617582e3171 in luaF_initupvals ../src/third_party/eris/lfunc.c:48
    #4 0x5617582d29a1 in u_closure ../src/third_party/eris/eris.c:1603
    #5 0x5617582d46a2 in unpersist ../src/third_party/eris/eris.c:2307
    #6 0x5617582d3518 in u_thread ../src/third_party/eris/eris.c:1892
    #7 0x5617582d46be in unpersist ../src/third_party/eris/eris.c:2313
    #8 0x5617582d0d5d in u_literaltable ../src/third_party/eris/eris.c:1013
    #9 0x5617582d13ae in u_special ../src/third_party/eris/eris.c:1154
    #10 0x5617582d13f7 in u_table ../src/third_party/eris/eris.c:1167
    #11 0x5617582d4694 in unpersist ../src/third_party/eris/eris.c:2304
    #12 0x5617582d0d5d in u_literaltable ../src/third_party/eris/eris.c:1013
    #13 0x5617582d13ae in u_special ../src/third_party/eris/eris.c:1154
    #14 0x5617582d13f7 in u_table ../src/third_party/eris/eris.c:1167
    #15 0x5617582d4694 in unpersist ../src/third_party/eris/eris.c:2304
    #16 0x5617582d22ca in u_upval ../src/third_party/eris/eris.c:1426
    #17 0x5617582d46da in unpersist ../src/third_party/eris/eris.c:2319
    #18 0x5617582d2a72 in u_closure ../src/third_party/eris/eris.c:1617
    #19 0x5617582d46a2 in unpersist ../src/third_party/eris/eris.c:2307
    #20 0x5617582d0d5d in u_literaltable ../src/third_party/eris/eris.c:1013
    #21 0x5617582d13ae in u_special ../src/third_party/eris/eris.c:1154
    #22 0x5617582d13f7 in u_table ../src/third_party/eris/eris.c:1167
    #23 0x5617582d4694 in unpersist ../src/third_party/eris/eris.c:2304
    #24 0x5617582d50e1 in unchecked_unpersist ../src/third_party/eris/eris.c:2558
    #25 0x5617582d59e3 in eris_undump ../src/third_party/eris/eris.c:2742
    #26 0x5617581f92d2 in unpersist_object(lua_State*, FileRead&, Widelands::MapObjectLoader&, unsigned int) ../src/scripting/persistence.cc:281
    #27 0x5617580f9524 in LuaGameInterface::read_global_env(FileRead&, Widelands::MapObjectLoader&, unsigned int) ../src/scripting/logic.cc:166
    #28 0x561757eb9cfc in Widelands::MapScriptingPacket::read(FileSystem&, Widelands::EditorGameBase&, bool, Widelands::MapObjectLoader&) ../src/map_io/map_scripting_packet.cc:72
    #29 0x561757933267 in Widelands::WidelandsMapLoader::load_map_complete(Widelands::EditorGameBase&, Widelands::MapLoader::LoadType) ../src/map_io/widelands_map_loader.cc:326