[PATCH] Updates to FXSR/SSE support in 2.4.0-test1

[Alan Cox]

> What happens when a signal occurs in a time slice where the application
> hasn't used the FPU?  Having the regular FPU environment around means we

You touch the FPU, it loads the FPU state you save both. If the FPU state
is already loaded it costs nothing. The FNSAVE stuff is horribly slow so
it is a real concern

> I'll play around with the conversion into/out of the signal handler and
> GETFPREGS request.  Should only take a short while, so don't do anything
> with the stuff I sent out yesterday.

Right now its correct, this is about being correct clean and fast so we are
going the right way