possible fix for the ULongArray issue and for mode_t portability

[danwallach]

This won't compile on my computer, possibly due to some kind of version mismatch issue:

> Task :linkDebugTestNative FAILED
e: Compilation failed: The /Library/Developer/CommandLineTools/usr/bin/clang++ command returned non-zero exit code: 1.
output:
error: Invalid record
1 error generated.

 * Source files: 
 * Compiler version info: Konan: 1.7.10 / Kotlin: 1.7.20
 * Output kind: STATIC_CACHE

e: org.jetbrains.kotlin.konan.KonanExternalToolFailure: The /Library/Developer/CommandLineTools/usr/bin/clang++ command returned non-zero exit code: 1.
output:
error: Invalid record

But there's at least a chance this might work for you. Please check it out. Of note, I think I've got a portable solution to the mode_t issue, and I moved everything from ULongArray to LongArray and the compiler at least seems to be happy with that. It shouldn't make a difference (fingers crossed) because all of the real compute on those happens inside HACL, which doesn't care.

That said, all the useNative stuff now quietly converts LongArray to CPointer<ULongVar>. This feels bad somehow, even though it keeps the code as clean as possible.

Note: to get this to work at all on my M1 Mac, I had to comment out the OptimizeForArchitecture.cmake file. (Related issue: #66). That's probably going to slow things down significantly if we don't find an alternative.