If the executable is compiled with gcc, the developer might need to use the -O2 flag (or -O3) so the code is still readable for Windows Defender.
With that said, Windows Defender is not great at detecting actual threats. Some online 'wisdom' is to ignore it by putting the executable in a folder that you'll mark for Defender not to scan. But you should still always use a virus scanner, and perhaps even submit the file for online virus checking (such as VirusTotal).