[tex-live] tlmgr invokes cc on OS X

[Adam R. Maxwell]

A user reported that running my TeX Live Utility application on Mac OS X
10.9 (released last week) is causing a prompt to install the Xcode
developer tools. After installing on a system without dev tools, I've
confirmed that tlmgr is causing this.

Apparently tlmgr is invoking the C compiler with cc, and Apple is now
shipping a stub application with the OS that puts up an alert saying
(paraphrased) "You don't have cc, but would you like to go install it?"

This is going to confuse users and create some support hassles. Is there
any way to stop tlmgr from doing this on OS X? I couldn't find it in the
Perl code, so maybe this is from config.guess?

thanks,
Adam