node: Add support for android

Resolves minor discrepancies between android and standard
POSIX systems. In addition, some configure parameters were
added, and a helper-script for android configuration.
Ideally, this script should be merged into the standard
configure script.

To build for android, source the android-configure script
with an NDK path:

> source ./android-configure ~/android-ndk-r8d

This will create an android standalone toolchain and export the
necessary environment parameters.

After that, build as normal:

> make -j8

After the build, you should now have android-compatible NodeJS
binaries.