First I should note that I'm usin macOS Sierra (version 10.12 beta 16A238m), but I don't think it's that different than El Capitan in this certain situation (but I guess you know more than I do about that, or I wouldn't be here right now asking this question).
So I installed GDB (The GNU Debugger) for following among a book I am currently reading ("Hacking: The Art of Exploitation"), which only explains how to use GDB, so I can't use LLDB. I installed it using Homebrew (brew install gdb), and everything worked fine. Until I used it.
I compiled my C source code using clang -g hello_word.c -o hello_world (it's just a simple C "Hello, World!" program), and then I run gdb -q hello_world, and here's the session:
So I googled a bit about codesigning, and found this. So I went through the instructions (except for the ones for Snow Leopard), and it still doesn't work! Anyone knows how I can make it work?