Fix build with MSVC.
Fix build with MSVC.

Thanks to Robin Huang for the patch.

drizt/qjson,qlands/qjson,coolshou/qjson,flavio/qjson,seem-sky/qjson,seem-sky/qjson,qlands/qjson,flavio/qjson,coolshou/qjson,drizt/qjson,gentlefn/qjson,cbranch/qjson-qmakefriendly,cbranch/qjson-qmakefriendly,gentlefn/qjson