Use kinfo_getvmmap on FreeBSD to enumerate memory regions.

Use kinfo_getvmmap on FreeBSD to enumerate memory regions.

Use kinfo_getvmmap from libutil on FreeBSD to enumerate memory
regions in a running process instead of /proc/<pid>/map.  FreeBSD systems
do not mount procfs by default, but kinfo_getvmmap uses a sysctl that
is always available.

Skip memory regions for devices as well as regions an application has
requested to not be dumped via the MAP_NOCORE flag to mmap or
MADV_NOCORE advice to madvise.

gdb/ChangeLog:

	* configure.ac: AC_CHECK_LIB(util, kinfo_getvmmap).
	* configure: Regenerate.
	* config.in: Regenerate.
	* fbsd-nat.c [!HAVE_KINFO_GETVMMAP] (fbsd_read_mapping): Don't
        define.
	(fbsd_find_memory_regions): Use kinfo_getvmmap to
	enumerate memory regions if present.