[feature request] a cross platform find GNU GCC macro

Following this discussion, we have the issue that we can't find the GNU GCC (gcc, g++, and gfortran) installed via HomeBrew on macOS. There might some temporary workaround for this specific issue, but it would be great if we could have script/macro (e.g., findGCC.cmake) that would fine the GNU compilers automatically. Thanks for your kind support in advance.

P.S.1. I also posted this here on CMake Discourse.

P.S.2. I just created a Discord channel for CMake. Feel free to join if you like chat services.

P.S.3. I also posted this here on Reddit and there are some comment(s).