scuzqy

Use "constexpr if" when possible

1

One more c++ 17 feature. Defined macro in rapidjson.h.

Resolve TODO in aligned_allocator

1

And updated corresponding test. AllocateAligned was designed to take POD types only. I also removed `TestAllocateAlignedObjectWithoutDestructor` because objects with constructor/destructor are obviously illegal input. btw, restriction here can be one...

`WIN32` was usually defined in minwindef.h, which is no longer included by most MSVC STL headers. _WIN32 is a predefined MACRO, it should fit here. error: ``` mainwindow_RunTime.cpp.obj : error...