See Build/Docs.
Create this file in the root of your project and you can add settings used by the GNU Make toolchain.
Enable debug mode. Necessary for MinGW64 to work with GDB, and to get logging while debugging with GDB
Enable release mode. This generates optimized code, enables stripping, and other things useful for generating a sharable executable.
Enables static linking mode. Not supported everywhere, but where it is you'll get a larger executable with fewer dependencies. Enabled by default on certain targets.