Re-add autoconf files

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>
Force 16-byte stack alignment

Allow SSE instructions in kernel modules

Seen on Debian jessie and other places:

[...]/testsuite/kern/latency/latency-module.c:1:0: error:
    -mpreferred-stack-boundary=3 is not between 4 and 12

http://mail.rtai.org/pipermail/rtai/2013-December/026198.html

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>
x86 default .config:  CONFIG_RTAI_CPUS="8"

Reported by Mick/Schooner/@ArcEye

Kernel crashes if number of host CPUs is greater than
`CONFIG_RTAI_CPUS`

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>