games/nxengine: unbreak with libc++ 7

In file included from src/i18n/translate.cpp:2:
src/i18n/../common/json.hpp:1379:9: error: static_assert failed "could not find from_json() method in T's namespace"
        static_assert(sizeof(BasicJsonType) == 0,
        ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~
src/i18n/../common/json.hpp:1388:16: note: in instantiation of function template specialization 'nlohmann::detail::from_json_fn::call<nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer>, std::__1::basic_string_view<char, std::__1::char_traits<char> > >' requested here
        return call(j, val, priority_tag<1> {});
               ^
src/i18n/../common/json.hpp:6860:9: note: in instantiation of function template specialization 'nlohmann::detail::from_json_fn::operator()<nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer>, std::__1::basic_string_view<char, std::__1::char_traits<char> > >' requested here
        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
        ^
src/i18n/../common/json.hpp:9579:36: note: in instantiation of function template specialization 'nlohmann::adl_serializer<std::__1::basic_string_view<char, std::__1::char_traits<char> >, void>::from_json<const nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer> &, std::__1::basic_string_view<char, std::__1::char_traits<char> > >' requested here
        JSONSerializer<ValueType>::from_json(*this, ret);
                                   ^
src/i18n/../common/json.hpp:9842:16: note: in instantiation of function template specialization 'nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer>::get<std::__1::basic_string_view<char, std::__1::char_traits<char> >, std::__1::basic_string_view<char, std::__1::char_traits<char> >, 0>' requested here
        return get<ValueType>();
               ^
/usr/include/c++/v1/string:875:29: note: in instantiation of function template specialization 'nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer>::operator basic_string_view<std::__1::basic_string_view<char, std::__1::char_traits<char> >, 0>' requested here
        {__self_view __sv = __t; return assign(__sv);}
                            ^
src/i18n/translate.cpp:22:34: note: in instantiation of function template specialization 'std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::operator=<nlohmann::basic_json<std::map, std::vector, std::__1::basic_string<char>, bool, long, unsigned long, double, std::allocator, adl_serializer>, void>' requested here
            _strings[ it.key() ] = it.value();
                                 ^

PR:		230630
Obtained from:	upstream (json-3.2.0)
Approved by:	portmgr blanket

1 files changed, 63 insertions, 0 deletions

diff --git a/games/nxengine/files/patch-libc++7 b/games/nxengine/files/patch-libc++7
new file mode 100644
index 000000000000..f50b04c91d75
--- /dev/null
+++ b/games/nxengine/files/patch-libc++7
@@ -0,0 +1,63 @@
+https://github.com/nlohmann/json/commit/8165707990e4
+
+--- src/common/json.hpp.orig	2018-04-09 20:44:59 UTC
++++ src/common/json.hpp
+@@ -840,6 +840,16 @@ struct is_compatible_object_type_impl<true, RealType, 
+         std::is_constructible<typename RealType::mapped_type, typename CompatibleObjectType::mapped_type>::value;
+ };
+ 
++template<bool B, class RealType, class CompatibleStringType>
++struct is_compatible_string_type_impl : std::false_type {};
++
++template<class RealType, class CompatibleStringType>
++struct is_compatible_string_type_impl<true, RealType, CompatibleStringType>
++{
++    static constexpr auto value =
++        std::is_same<typename RealType::value_type, typename CompatibleStringType::value_type>::value;
++};
++
+ template<class BasicJsonType, class CompatibleObjectType>
+ struct is_compatible_object_type
+ {
+@@ -850,6 +860,15 @@ struct is_compatible_object_type
+                                   typename BasicJsonType::object_t, CompatibleObjectType >::value;
+ };
+ 
++template<class BasicJsonType, class CompatibleStringType>
++struct is_compatible_string_type
++{
++    static auto constexpr value = is_compatible_string_type_impl <
++                                  conjunction<negation<std::is_same<void, CompatibleStringType>>,
++                                  has_value_type<CompatibleStringType>>::value,
++                                  typename BasicJsonType::string_t, CompatibleStringType >::value;
++};
++
+ template<typename BasicJsonType, typename T>
+ struct is_basic_json_nested_type
+ {
+@@ -1132,6 +1151,25 @@ void from_json(const BasicJsonType& j, typename BasicJ
+     {
+         JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
+     }
++    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
++}
++
++template <
++    typename BasicJsonType, typename CompatibleStringType,
++    enable_if_t <
++        is_compatible_string_type<BasicJsonType, CompatibleStringType>::value and
++        not std::is_same<typename BasicJsonType::string_t,
++                         CompatibleStringType>::value and
++        std::is_constructible <
++            BasicJsonType, typename CompatibleStringType::value_type >::value,
++        int > = 0 >
++void from_json(const BasicJsonType& j, CompatibleStringType& s)
++{
++    if (JSON_UNLIKELY(not j.is_string()))
++    {
++        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
++    }
++
+     s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
+ }
+