[droid] - allow to build android for x86 platforms

As the title says. This is more of a RFC. As you can see there are some strange mixups here where we checked for toolchains like android-linux-gnu. I have adapted it so it compiles with my osx toolchain which is called i686-linux-android (which is inline with the arm*-linux-android naming sheme).

Maybe someone ( @tnelson volunteered? :D) could check the x86 toolchain name on linux.

I have test compiled this with vanilla android ndk r9 (gcc 4.7 toolchain).

pythonmodule-pil is still unsolved when compiled from osx host (not sure if this is an issue on linux aswell). @theuni was informed and pinged for that already ;) (for my testbuilds i just skipped building it...)