If anybody is interested in Ada on the 64-bit ARMv8 architecture, there are a couple more options available to you today.

Last week I created a FreeBSD/DragonFly to FreeBSD64/ARM cross-compiler and placed it in ports: http://www.freshports.org/lang/gnatcross-aarch64/
That compiler was based on previous GnatDroid work.

Over the weekend, I used that cross-compiler to fully bootstrap FSF GCC 6.3.1 to FreeBSD/ARM64.

I also mentioned this news on my (mostly neglected) DragonLace website

Hopefully somebody finds this work useful!.

John