[grsec] consider splitting grsecurity

[spender at grsecurity.net]

> well, then check your diffs, because you have much left out from current 
> pax. That's why I say, split it. PaX is maintained separately. There is 
> almost no conflict between PaX and the rest of grsec, only where you 
> decided to not account from VM_MIRROR (and that haven't changed much in 
> the last time), so that conflict can be easily adapted (not considering 
> the changes you have done not using asm/page.h and similar, changed to 
> use grsecurity/Config.in instead of what was provided by 
> PaX, but that does not change any functionality), and it's more accurate, 
> consider only the fact that some time ago some PaX option that was
> allowed only on 586_TSC was possible on grsec w/o this condition, 
> producing some noise/failures.

I've gone through an entire check of the differences between grsec and 
PaX and copied over the changes (page.h, fixed pageexec config, amd64, 
mips, mips64, ia64 support).

-Brad