>Unless you mean a different thing, that can be achieved and >is already done in some packages. For example, mplayer has a >USE flag called custom-cflags which freely allow you to break >it as much as you want.
What I meant was something like this: supposed that the maintainer of a particular package knows the -O3 causes a massive performance increase (just an example, I know that usually -03 only gives marginally better performance and that it can even make stuff slower), if the user has the "simmonsays" USE flag enabled, that package will be built with -03, respecting the users' -march setting but overriding -On. Developing the idea, there could be a "performance" and a "stability" USE flags, that would use the recommended CFLAGS for each package, some sort of "automated ricing" ;-)
