As documented at
https://developer.apple.com/library/ios/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html,
the ARM64 iOS ABI differs from the generic ABI in a few important
ways. Specifically, arguments passed via the stack are aligned
according to their natural alignment instead of 8 bytes. The VM's
dynamic call code was aligning each argument to 8 bytes, so native JNI
code couldn't find them in their expected places.
Also, we weren't setting the "os.arch" system property on ARM64, so I
fixed that too.
Recent versions of jni.h such as the one provided by Debian Jessie's
OpenJDK define UNUSED in a way that conflicts with our definition and
usage, so we need to explicitly undefine it before redefining it to
avoid compiler noise.
Previously, I used a shell script to extract modification date ranges
from the Git history, but that was complicated and unreliable, so now
every file just gets the same year range in its copyright header. If
someone needs to know when a specific file was modified and by whom,
they can look at the Git history themselves; no need to include it
redundantly in the header.