spec: make pax plugin support configurable

Signed-off-by: David Sterba <dsterba@suse.cz>
spec: use grsec as a variant, add i386, x86_64 and armv6hl configs

Copy distro configs to grsec flavors.  Disable CONFIG_SPLIT_PACKAGE,
CONFIG_X86_X32.  Enable CC_STACKPROTECTOR, set buffer size to 4.

Enable Set CONFIG_PAX_EMUTRAMP

"From: Anthony G. Basile <blueness@gentoo.org>

PAX_EMUTRAMP is needed for libffi to avoid RWX mmap-ings using PaX
emulation of trampolines.
We default PAX_EMUTRAMP='y' since almost all hardened users will want
this.

See bug:
 http://bugs.gentoo.org/show_bug.cgi?id=329499
 http://bugs.gentoo.org/show_bug.cgi?id=457194
"

For arm6hl: Disable lustre, breaks build.

Signed-off-by: David Sterba <dsterba@suse.cz>