core_pattern: allow passing of arguments to user mode helper when core_pattern is...

A rewrite of my previous post for this enhancement.  It uses jeremy's
split_argv/free_argv library functions to translate core_pattern into an argv
array to be passed to the user mode helper process.  It also adds a
translation to format_corename such that the origional value of RLIMIT_CORE
can be passed to userspace as an argument.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>