Uninitialized variable warnings

[pieterlexis]

Found while compiling dnsdist 1.3.0 on Arch Linux.

• gcc --version: gcc (GCC) 7.3.1 20180312

In file included from dnsdist.hh:24:0,
                 from dnsdist-lua-inspection.cc:22:
ext/luawrapper/include/LuaContext.hpp: In static member function ‘static int LuaContext::Pusher<TReturnType(TParameters ...)>::push(lua_State*, TFunctionObject) [with TFunctionObject = setupLuaInspection()::<lambda(unsigned int, boost::optional<int>)>; TReturnType = std::unordered_map<unsigned int, std::vector<boost::variant<std::__cxx11::basic_string<char>, double> > >; TParameters = {unsigned int, boost::optional<int>}]::<lambda(lua_State*)>::_FUN(lua_State*)’:
ext/luawrapper/include/LuaContext.hpp:1806:68: warning: ‘*((void*)&<anonymous> +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             return function(param, std::forward<TParams>(params)...);
                                                                    ^
ext/luawrapper/include/LuaContext.hpp: In static member function ‘static int LuaContext::Pusher<TReturnType(TParameters ...)>::push(lua_State*, TFunctionObject) [with TFunctionObject = setupLuaInspection()::<lambda(boost::variant<std::__cxx11::basic_string<char>, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >, boost::optional<unsigned int>)>; TReturnType = void; TParameters = {boost::variant<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >, boost::optional<unsigned int>}]::<lambda(lua_State*)>::_FUN(lua_State*)’:
ext/luawrapper/include/LuaContext.hpp:1806:68: warning: ‘*((void*)&<anonymous> +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             return function(param, std::forward<TParams>(params)...);
                                                                    ^
  CXX      dnsdist-protobuf.o
In file included from dnsdist.hh:24:0,
                 from dnsdist-lua.cc:31:
ext/luawrapper/include/LuaContext.hpp: In function ‘static typename std::enable_if<LuaContext::IsOptional<TFirstType>::value, TRetValue>::type LuaContext::readIntoFunction(lua_State*, LuaContext::tag<TRetValue>, TCallback&&, int, LuaContext::tag<TObject>, LuaContext::tag<TTypes>...) [with TRetValue = void; TCallback = LuaContext::Binder<LuaContext::Binder<LuaContext::Binder<setupLuaConfig(bool)::<lambda(const std::vector<std::pair<unsigned int, std::__cxx11::basic_string<char> > >&, const string&, boost::optional<int>, boost::optional<DNSAction::Action>)>&, const std::vector<std::pair<unsigned int, std::__cxx11::basic_string<char> > >&>&, const std::__cxx11::basic_string<char>&>&, const boost::optional<int>&>&; TFirstType = boost::optional<DNSAction::Action>; TTypes = {}]’:
ext/luawrapper/include/LuaContext.hpp:1806:68: warning: ‘*((void*)&<anonymous> +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             return function(param, std::forward<TParams>(params)...);
                                                                    ^
ext/luawrapper/include/LuaContext.hpp: In static member function ‘static int LuaContext::Pusher<TReturnType(TParameters ...)>::push(lua_State*, TFunctionObject) [with TFunctionObject = setupLuaConfig(bool)::<lambda(boost::optional<unsigned int>)>; TReturnType = void; TParameters = {boost::optional<unsigned int>}]::<lambda(lua_State*)>::_FUN(lua_State*)’:
ext/luawrapper/include/LuaContext.hpp:1806:68: warning: ‘*((void*)&<anonymous> +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             return function(param, std::forward<TParams>(params)...);
                                                                    ^
ext/luawrapper/include/LuaContext.hpp: In function ‘static typename std::enable_if<(! LuaContext::IsOptional<TFirstType>::value), TRetValue>::type LuaContext::readIntoFunction(lua_State*, LuaContext::tag<TRetValue>, TCallback&&, int, LuaContext::tag<TObject>, LuaContext::tag<TTypes>...) [with TRetValue = std::shared_ptr<DownstreamState>; TCallback = setupLuaConfig(bool)::<lambda(boost::variant<std::__cxx11::basic_string<char>, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::variant<bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::function<std::tuple<DNSName, short unsigned int, short unsigned int>(const DNSName&, short unsigned int, short unsigned int, dnsheader*)> >, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::variant<bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::function<std::tuple<DNSName, short unsigned int, short unsigned int>(const DNSName&, short unsigned int, short unsigned int, dnsheader*)> > > > > >, boost::optional<int>)>&; TFirstType = boost::variant<std::__cxx11::basic_string<char>, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::variant<bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::function<std::tuple<DNSName, short unsigned int, short unsigned int>(const DNSName&, short unsigned int, short unsigned int, dnsheader*)> >, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::variant<bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::vector<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::function<std::tuple<DNSName, short unsigned int, short unsigned int>(const DNSName&, short unsigned int, short unsigned int, dnsheader*)> > > > > >; TTypes = {boost::optional<int>}]’:
ext/luawrapper/include/LuaContext.hpp:1806:68: warning: ‘*((void*)&<anonymous> +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             return function(param, std::forward<TParams>(params)...);
                                                                    ^