This is the minimum amount of machinery necessary to get
libgojni.so loading and callable from an Android App.
To keep impact on the Go runtime small, we construct an
auxv array here from /proc/self/auxv.
LGTM=minux, adonovan
R=adonovan, golang-codereviews, minux, bradfitz
CC=golang-codereviews
https://golang.org/cl/107500043