gb libaws_2.10.2-4 . armhf

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Please re-attempt to build libaws on armhf. The last attempt
used gnat-4.6 4.6.3-3 and failed.  Currently gnat-4.6 4.6.4-4
is in testing and its changelog contains:

* Fix setting MULTILIB_DEFAULTS for ARM multilib builds.

which is likely fix the build issue; other libraries built
fine with gnat-4.6 4.6.4-4 on armhf.

Thanks.

--
Ludovic Brenta.