If you do need to extend the system, then it is best to use option names similar to existing ones. For instance, -z and -Z are assumed to be linker options, so if you need a new linker option then something like -zthis or -Zthat might be a good choice. This trick is used by darwin which supports a slew of -Z* options that look mostly like special linker options.
Let me further clarify. There are a host of linker options that we translate (grep TRANSLATE in darwin.h) into -Z options, that start out with otherwise conflicting names -segblabla...
