Add GCC & G++ Support

[devishraq]

It would be highly beneficial to add GCC and G++ compiler support to Zed.
This feature would allow users to perform competitive programming directly within the editor, leveraging its high performance and multiplayer capabilities.
By integrating these compilers, users can write, compile, and test their C++ code seamlessly without needing to switch to external tools. This addition would enhance the overall coding experience for competitive programmers who rely heavily on these compilers.

Current clangd support is not enough for cp ... gcc support will enhance the total workflow in cp.