libcxx on older systems (eg 10.6) test and fixes format

[Lawrence Velázquez]

On Aug 13, 2016, at 11:11 AM, Ken Cunningham
<ken.cunningham.webuse at gmail.com> wrote:

> I just realized that MINOR is a qt4-mac specific global, not
> a Macports global. And it seemed so handy for what I wanted to do.
> 
> Damn. Bad start to this thread. Let me try again another day.

No need:

	if {${os.platform} eq "darwin" && ${os.major} <= 10
	        && ${configure.cxx_stdlib} eq "libc++"} {
	    # Snow Leopard and earlier
	}

Tiger is 8, Leopard 9, etc.

As I mentioned in one of the tickets you opened, I don't see a need to
check the OS unless the fix actually breaks things on newer OSes,
although I guess there's something to be said for being as specific as
possible.

vq