Here’s how to download Mac OS X El Capitan DMG file also. MacOS X El Capitan is a stable version of OS X and it is quite different and known as the advanced version of Mac. This operating system contains countless supplements and a variety of work capacities. How to install and codesign GDB on OS X El Capitan. May 12, 2016 3 min read. Disclaimer: this was tested under OS X 10.11.3 and 10.11.4 bu..