`xcode-select –install` required for OS X 10.9 Xcode command-line tools (like `zlib-devel`)
Posted by jpluimers on 2016/11/16
Hopefully this was a one time oversight from Apple, but on OS X 10.9 (Mavericks) the Xcode command-line tools cannot be installed from the Xcode Preferences pane.
You have to install them from the command-line:
There is one catch though: it might fail as you first have to start Xcode once and accept the license agreement.