This patch depends on the i386 MTRR driver cleanup I sent earlier.

 - Support non executable mappings for x86-64. data/heap are non executable
   by default now.
 - Beginnings of software suspend from Pavel (not working yet)
 - Support generic compat functions and remove some shared code
   in the 32bit emulation (Stephen Rothwell)
 - Support hugetlbfs
 - Some makefile updates
 - Make sure all 32bit emulation functions return long, not int.
   This fixes some problems with ERESTARTNOSYS.et.al. leaking to userspace.
 - Add new system calls.
 - Fix long standing fs/gs context switch bugs (thanks to Karsten Keil
   for helping to fix that mess). Also make sure the gs selector is
   set to 0 after an exec.
 - Simplify TLS switching
 - Paranoid CPUID check at bootup
 - Reorder scatterlist to be more space efficient (Jes Soerensen)
 - Enlarge 32bit address space to full 4GB.
 - Beginnings of 32bit SYSCALL support (not completely working yet
   and vsyscall page miss yet)
 - Various merges from i386
 - New module loader
 - Support threaded core dump (XMM saving for 32bit programs doesn't
   work, but it appears to be broken on i386 too)
 - Fix bug in signal stack rounding
 - Remove DRM 32bit emulation.
 - Use MTRR driver from i386
 - Use bootflag.c from i386
 - Various other fixes and cleanups.