android: Upgrade liboath

android: Upgrade liboath

liboath requires minor hacks to build with the latest NDK releases:

1) __freading() cannot be implemented, because older versions of
Bionic[0] do not keep track of the last operation on the stream.

2) Some of the autoconf checks need to be overridden from "cross" to
"yes".

3) Most of the stdio replacement code in gnulib doesn't compile,
because it requires access to internal libc structs.  The internals
are no longer exposed through NDK headers, and they vary from one
Android version to the next.

Fortunately, while these hacks would not pass muster upstream, they
are good enough for the special case of compiling liboath.

[0] https://android.googlesource.com/platform/bionic/+/android-8.1.0_r9/libc/stdio/stdio_ext.cpp#42

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>