The GNAT-to-Android/ARM cross-compiler known as GnatDroid-ARMv7 has been available on FreeBSD and DragonFly since even before it was officially supported in GCC.
I've produced a second cross-compiler, GnatDroid-x86 which targets the 32-bit Android/x86 platform.
The nice thing about Android/x86 is that it can be installed on a virtual machine like VirtualBox, so it can be easier to test programs without actual hardware as for GnatDroid-ARMv7.
GnatDroid is only available on FreeBSD and DragonFly BSD, although somebody could replicate the effort for other platforms if so desired: http://www.freshports.org/lang/gnatdroid-x86
