Each target machine supported by GCC can have its own options—for example, to allow you to compile for a particular processor variant or ABI, or to control optimizations specific to that machine. Similarly, GCC also has options that are specific to particular operating systems or runtime environments on the target.
By convention, the names of machine-specific options start with ‘-m’. Some configurations of the compiler also support additional target-specific options, usually for compatibility with other compilers on the same platform.