Heap corruption with auth_gssapi on Windows, in FreeContextAttributes()

On Windows Server 2012 R2, in debug compiled mysqld (did not try optimized),
I see intermittent heap corruption when trying to use auth_gssapi authentication.

The line where it crashes is FreeContextAttrbutes() to free memory previously allocated previously with

QueryContextAttributes(ctxt, SECPKG_ATTR_NATIVE_NAMES, &native_names);

https://github.com/MariaDB/server/blob/df704b5a1b581f4f9a02b9310f2b2c8ef36eb98f/plugin/auth_gssapi/sspi_server.cc#L106

Apparently, FreeContextBuffer(&native_names) seems to be incorrect, since it refers
to structure on stack, rather than heap allocated by the structure members.