UBUNTU: ubuntu: nx-emu - i386: mmap randomization for executable mappings

UBUNTU: ubuntu: nx-emu - i386: mmap randomization for executable mappings

This code is originally from Ingo Molnar, with some later rebasing and
fixes to respect all the randomization-disabling knobs. It provides
address randomization algorithm when NX emulation is in use in 32-bit
processes. Kees Cook pushed the brk area further away in the case of PIE
binaries landing their brk inside the CS limit.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>