[MACTCL] Cocoa Tk built for OS X 10.10 fails during initialization

[Ned D. <na...@ac...>]

Heads up for OS X 10.10 Yosemite users: if you build a version of Cocoa 
Tk 8.6.x or 8.5.x for OS X 10.10, that is, either on 10.10 or with 
MACOSX_DEPLOYMENT_TARGET=10.10, Tk will abort during initialization with 
the error:

    Mac OS X 10.10000 or later required

The problem is due to an incompatible change in Apple's 
AvailabilityMacros, a change necessary due to the version number moving 
from one ('.9') to two ('.10') digits.

I've opened a Tk issue about the problem:

    https://core.tcl.tk/tk/tktview?name=1d37c3e166

Note that this doesn't affect those third-party Tk's built on earlier 
versions of OS X, for example ActiveTcl 8.5 and 8.6; the current 
versions of each run OK on 10.10 or, at least, they don't fail with this 
problem.  Also, X11 versions of Tk on OS X are not affected.

-- 
 Ned Deily,
 na...@ac...