Modifications to support android_arm 9 platform.
There are some manual steps for a successful build:
1. You must install the android ndk and run
android-ndk-install-dir/build/tools/make-standalone-toolchain.sh
to create the 'androidarm-tc' toolchain directory.
2. You must set environment variables
NDKROOT, TOOLCHAIN, SYSROOT
3. The final link command must be manually run to dynamically link
-lz. I couldn't figure out a way for scons to run the correct link command.