Enable build on OpenPOWER systems (ppc64le)

[madscientist159]

Fix overly simplistic architecture check.

We have been using Zimbra on POWER in production for around one year with this modification. Zimbra has been fast and reliable on these platforms.

[CLAassistant]

All committers have signed the CLA.

[madscientist159]

Note that in order to build on POWER, you do need to point zm-build at the fixed junixsocket source tree here:
https://github.com/madscientist159/junixsocket/tree/junixsocket-parent-2.0.4-ppc64le

That appears to be the only other modification required, but I don't expect Synacor will want to redirect that repo. For now, it's fairly easy to just redirect the junixsocket repo to build (this is the only action that POWER users will need to take after download once this pull request is merged).

This was tested with a full build of Zimbra 8.8.15 on a POWER9 / Talos II server. Zimbra is known to be functional since at least version 8.7 on POWER servers, and is currently being used in production on those servers at Raptor.

[Prashantsurana]

Thanks for the submission. The changes looks good to me.
However from Zimbra product point of view, we are not certifying/supporting the non-x86 environment. hence I will not merge the changes to develop.

[madscientist159]

Why can't we get the changes in place for unofficial / non-certified systems? We can attest to the fact that Zimbra works very well on POWER systems since we use them in production with our own builds...

[gerrith3]

So, I'm confused - Is Zimbra open source? And doesn't it embrace users that use open source, wherever and however they might use them? It seems like merging changes to enable additional features is typical in open source communities, even if they aren't supported by the corporate release, is typical. Is there some reason why you aren't taking additional features? Is the source base just for the corporately released/supported version? This is not typical in the open source communities that we usually work with.

[madscientist159]

Just wanted to revisit this and ask if we could get the decision not to merge revisited? POWER is seeing a wider deployment especially in this age of cyberattacks, and it is probably not a great idea to force use of the known-insecure Intel ME or AMD PSP to use Zimbra.