VariantInit() and friends are missing

[rickbrew]

https://docs.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-variantinit

I just started my first conversion from a C++/CLI wrapper to a C# one, and immediately bumped into things like VariantInit() being missing.

Also, VARIANT.vt and PROPVARIANT.vt should be a VARTYPE or VARENUM instead of ushort.

It looks like my VARIANT code mostly works by reinterpret-casting to PROPVARIANT and doing its work, so I'll update this issue if I see any missing Prop*() methods.

[rickbrew]

Looks like all of the InitPropVariantFrom___ methods from propvarutil.h are missing. These are macros though ...

[rickbrew]

The exports from propsys.dll seem to be missing, e.g. InitPropVariantFromBuffer https://docs.microsoft.com/en-us/windows/win32/api/propvarutil/nf-propvarutil-initpropvariantfrombuffer

[rickbrew]

DATE is missing, although it's just typedef double. See also DateTime::ToOADate(). Might not need this, it's super niche.

[rickbrew]

VARIANT_BOOL is also missing, although it's just typedef short

[rickbrew]

I've transcribed many of the inline methods from propvarutil.h : https://gist.github.com/rickbrew/2d54728ca99fe91476e01db622d39a8c

So far so good, not seeing an errors in my code so far ...