Missing COLE_DEFAULT_PRINCIPAL, COLE_DEFAULT_AUTHINFO constants

[riverar]

Originally posted in microsoft/windows-rs#2055.

Missing constants

#define	COLE_DEFAULT_PRINCIPAL	( ( OLECHAR * )( INT_PTR  )-1 )
#define	COLE_DEFAULT_AUTHINFO	( ( void * )( INT_PTR  )-1 )

[kennykerr]

Related to #1029

[AArnott]

These would look like:

    unsafe static char* COLE_DEFAULT_PRINCIPAL = (char*) -1;
    unsafe static void* COLE_DEFAULT_AUTHINFO = (void*) -1;

Assuming the OLECHAR should be considered 16-bit.

[mikebattista]

I did my best to define these.

I believe COLE_DEFAULT_PRINCIPAL is correct and aligns with the expected type in the API (PWSTR).

Less confident about COLE_DEFAULT_AUTHINFO (void*). I tried various combinations of definitions and most wouldn't make it to the winmd.