if you run an apple Operating System on other Hardware other than genuine Appe Hardware then you violate the EULA.
...and the EULA also states that you can only run two (2) virtualized copies of your MAC OS ontop of one (1) genuine Apple Computer, that also includes the "Server" addon, as it is seen as an addon to MAC OS.
Oh dear, oh dear, oh dear..
That would be all well and fine; however since OS X is a descendent/fork of BSD 4.4 (no arguments.. honestly), regardless of how much Apple rewrote - they have consented to the BSD4.4 license and must adhere to the agreement (and all clauses) they have entered into by using the BSD4.4 codebase.
There are several conditions that then apply; chief of which is '1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.'
The second is '2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.'; meaning that it is fine for Apple to use existing code - as long as they release the source code.
This appears in all different flavours of the license; so it is not unique to any one flavour.
I'm yet to see Apple do this; so they are clearly breaking the law.
Additionally; they have intentionally crippled what does exist already, so it only boots under certain hardware conditions.
Had they used the IBM 'clean room' approach (in regards to replication of functionality/API calls/compatibility) and rewritten using clear original notes; this wouldn't even be an issue for them, I'm not sure why they'd do this - but then again, looking at the quality of the machines they build (have you seen a MacBook Pro motherboard? or DVD drive? Absolute rubbish, built to be replaced upon failure), I'm guessing they didn't rewrite to keep their costs lower.
In short; Apple has reused a codebase but doesn't want to abide by the agreements set out by given codebase.
Even if they developed their codebase to the point where it had been rewritten incrementally, it would still be a descendant of BSD4.4.
How a multi-billion dollar conglomerate does this without facing the law is beyond me. Money talks, dirty money.
In short; do whatever you like with their software. Its not theirs.
These guys defending Apple are obviously fanboys (or idiots); take their advice with a grain of salt.
Apple's introduction of UEFI into the marketplace is the result of a sore and bruised ego after being forced to move their entire computer product line from a proprietary line of hardware to Intel architecture; as they desperately tried to stay competitive, and as a result has ruined computing for the rest of the industry (further hammered into place by Microsoft using UEFI; and Redhat bending over and buying a certificate).
Meaning you don't have the right (or means) to run whatever OS you like; on your own computer.
Go to hell Apple.
People will do whatever they like with your software regardless (usually just to compile a flavour of their application for your OS and delete the install once done).