With Mavericks Update, Apple has replaced GDB by LLDB, which is a part of the LLVM suit.
It might have been a good move on Apple’s side as it includes tons of new features and is also catching up with gdb on the run-time performance part (you can read more about it here). But I needed GCC and GDB for one of my projects and so here goes a post about it.
You can get GCC by installing Command-line-tools package in OS X.
If you hit
gcc in terminal it will prompt you for installing command line tool package, you can also fetch it directly from Apple dev download section https://developer.apple.com/downloads/.
But that comes with LLDB as the debugger, unlike previous releases of OS X (till Mountain Lion) which included GDB too.