This utility will set the SELinux mode to "Permissive"

Download the Android Native Development Kit (NDK): http://developer.android.com/tools/sdk/ndk/index.html#Downloads

Extract that into a directory and make sure that's on your PATH export PATH=/place/where/unzipped:$PATH

Build the image using ndk-build NDK_PROJECT_PATH=. APP_BUILD_SCRIPT=./Android.mk

The program will be written to ./libs/armeabi/selinuxoff

If the phone you're running this on is "known", then this can be run as a non-root user. Otherwise, it will require root to be able to find the necessary kernel address.