Support for PPC64BE / IBM AIX

[ningvin]

With MIR version 1.0.0, support for PPC64BE has been removed. The reason given is that POWER7, the last big endian CPU, is fairly old at this point.

While POWER7 technically is indeed the last pure big endian CPU in the Power series¹, more recent Power ISAs (POWER8 and onwards) can run in both big and little endian mode. AFAIK, Linux distributions are available for both flavors.

The push has been more to the little endian side in recent years as it is easier to port from x86-64 to PPC64LE and vice versa. There is however one OS that still holds out in big endian waters: IBM AIX.

My question therefore is the following: would it be possible / feasible to re-add support for PPC64LE with the aim of supporting IBM AIX? This could be as simple as reverting 96a7c67, though I suspect there may be some things that would require more work (ABI / calling conventions / ...). To make matters worse, getting access to a recent AIX system seems to be a pain (unless money is of no concern).

I may play around with this a bit when time permits, but wanted to clarify if this aligns with MIR's goals / standards before putting time into a pull request.

Footnotes

1. There may have already been some little endian capabilities though ↩