sysvinit: allow stack size configuration from rcS

sysvinit: allow stack size configuration from rcS

For certain swap/overcommit settings (e.g. when overcommit is disabled
on a real-time system), we need to limit the stack size used by
initscripts.  When the STACK_SIZE environment variable is set (usually
in /etc/default/rcS), ulimit the stack size to the value specified.

Make the stack size ulimit a soft limit, which allows the user to
increase the stack size where required without having to run the
respective application as root.

(From OE-Core rev: 0b5db16929de7668174e74e428f3e4e90e76e1d8)

Signed-off-by: Scot Salmon <scot.salmon@ni.com>
Signed-off-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Ben Shelton <ben.shelton@ni.com>
Acked-by: Rich Tollerton <rich.tollerton@ni.com>
Acked-by: Brad Mouring <brad.mouring@ni.com>
Acked-by: Bill Pittman <bill.pittman@ni.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>