[tlbuild] aarch64/armv8h binary distribution?

[Karl Berry]

Hi Johannes (and all),

    Date: Wed, 1 Nov 2017 02:39:55 +0100
    [...]
    libpng not properly handling the presence of NEON instructions on
    AArch64.

I've attempted to import the neon stuff from the upstream files. (I did
not do anything with the non-neon hardware optimizations.)

So, theoretically, giving --enable-arm-neon=check (or =api) to TL's
configure (or Build) should now do something.  I don't have any relevant
machine to actually try a compile on, but it did still compile for me on
my centos7.

Please give it a try when you can and let me know what goes
wrong. Surely something will :). --thanks, karl.