bug#27810: NS runtime feature detection

[Glenn Morris]

Alan Third wrote:

> I think perhaps we need to just test '< 10.7'. I've attached a new
> patch that deals with that and some other bits and pieces.
[...]
> I'm unclear where we should be using MIN_REQUIRED vs MAX_ALLOWED, but
> I think we're OK with MAX everywhere for what we're doing. I've just
> used MAX in both my new macros.
>
> We need a proper runtime OS version check in a few places. I think
> there are two ways of doing this depending on which OS version you're
> building on. It's getting very close to circular. ;)
>
> macfont.m looks like it could be a small nightmare as it has a LOT of
> version dependent code.


FWIW, a comment from someone who is disinterested in OS X:

You could probably make your life easier by not supporting more
than Apple does. Eg on the net I read:

    Apple is only supporting Mac OS X 10.9 – 10.11. Apple stopped
    providing security updates for Mac OS 10.8 and earlier versions with
    the release of Mac OS X 10.11 (El Capitan) in 2015.