As of December 31, 2018, FreeSWITCH will no longer be tested on OS X El Capitan. Apple dropped support and no longer issues security patches. Also, Homebrew also no longer officially supports El Capitan.
FreeSWITCH installed and worked fine on El Capitan as of the dates below. If desiredTo install, follow the Xcode instructions below, then follow the manual installation instructions.
Download Xcode (No Longer Required as of December 2017)
Xcode takes a while to download and is placed into the Applications folder (/Applications directory) with the Command Line Tools in /Applications/Xcode.app/Contents/Developer.
This Xcode Download requires you to sign in with your Apple ID and agree to the Software Agreement:
El Capitan 10.11: download and install Xcode 7.3.1 from Xcode 7.3.1 Download then start Xcode. NOTE: Xcode 8 CANNOT be used. See FS-9521.