Not sure why this warning is being emitted; let's reexamine it on the
next libunwind upgrade. I triggered it with this:
zig c++ -o hello hello.cpp -target x86_64-windows
also start prefering NtDll API. so far:
* NtQueryInformationFile
* NtClose
adds a performance workaround for windows unicode conversion. but that
should probably be removed before merging