libuv: backport android stat(2) timestamps patch

With this patch, cjdns can be built for an Android x86 target,
e.g. the emulator. Android's bionic libc doesn't provide
stat->st_atim/mtim/ctim as per POSIX-1.2008. More information
can be found in the upstream pull request.

https://github.com/joyent/libuv/pull/1506