Refactor and expose core-dumping functionality

Refactor and expose core-dumping functionality

This commit exposes the functions that dump core outside utils.c.
can_dump_core gains a new parameter, "limit_kind", to allow either
the soft or hard limit to be checked, and its printing has separated
into the new function warn_cant_dump_core.  The new function
can_dump_core_warn does what can_dump_core previously did (print and
warn).

gdb/
2014-06-19  Gary Benson  <gbenson@redhat.com>

	* utils.h (resource_limit_kind): New enum.
	(can_dump_core): New declaration.
	(warn_cant_dump_core): Likewise.
	(dump_core): Likewise.
	* utils.c (dump_core): Made nonstatic.  Added new
	parameter "limit_kind".
	(can_dump_core): Made nonstatic. Moved printing code to...
	(warn_cant_dump_core): New function.
	(can_dump_core_warn): Likewise.
	(internal_vproblem): Replace calls to can_dump_core with
	calls to can_dump_core_warn.  Supply new argument to each.