about Qt 5.x and OS X 10.6

[René J.V. Bertin]

Hello,

As you know I've been investing quite a bit of work in bringing Qt 5.4.x to MacPorts, and to make Qt 5 co-installable with Qt 4. In fact, I started with the latter, and then moved on to the former. And in that 2nd step I completely forgot that Qt 5.4.x no longer build on OS X 10.6 (and earlier).

I don't like the idea of holding off on Qt 5.4 for the sake of "SL" (much as I love it), nor do I like the idea of dropping Qt 5 support for "SL" (because I love it too much for that :)) 
So I am now exploring an option that may be a bit unusual: OS-specific port versions. Nothing as fancy as it seems: for OS X 10.6 users port:qt5-mac-devel will appear to be at 5.3.2 and for all other users it will appear to be at 5.4.x .

I'm posting this on macports-users (instead of ~-dev) to see if 1) this is a viable and acceptable approach (for the core devs) and 2) an appreciated approach (for the users).

I'm aware that this could set precedence, because it might well be that Qt 5.5 will no longer build on OS X 10.7 (and 5.6 on 10.8 and so forth). As far as I'm concerned this approach allows me to centralise portfile development and maintenance in a single file. I foresee to re-evaluate the situation when Qt 5.5 is released; if necessary I'll create a qt53-mac port for "SL" and move Qt 5.4.x to the "legacy fallback" code in the qt5-mac port, but that's not the only option to keep the main portfile complexity in check.

Thanks,
R.