Instead of adding the rtl_vista library to the target, manually add
the related source files to compilation. That's not the best, but
this should definitively fix the linking problem.
The reason is that both RtlUTF8ToUnicodeN() and RtlUnicodeToUTF8N() are
exported in both kernel and user-mode (ntdll) in Windows 7+.
Conversion from and to UTF8 are fundamental enough that they indeed
deserve to be in a separate file.
for vista+ APIs implemented in ntoskrnl_vista.
Now if you statically link ntoskrnl_vista into a driver,
NTKERNELAPI will automatically be removed from an API definition
