macOS: Remove outdated condition for CMAKE_OSX_DEPLOYMENT_TARGET

Revert commit 2853326e7a (BUG: Only set CMAKE_OSX_DEPLOYMENT_TARGET on
Mac OSX 10.4 or later, 2009-01-27, v2.8.0~1169).  AFAIK no one is using
macOS versions older than 10.4 anymore.
1 file changed