How to get Apple Command Line Developer Tools without App Store?
Just get an Apple ID enter payment information for an Apple ID so that it can be used with App Store. You might eventually need it for upgrading the OS or for installing applications.

If others find this question after developer.apple.com comes back up, you can download the Command Line Tools package from https://developer.apple.com/downloads. It can also be installed from Xcode's preferences, but most of the binaries are already in /Applications/Xcode.app/Contents/Developer/{usr/bin,Tools}.