Require kinfo_get_file and kinfo_get_vmmap for FreeBSD hosts.

Require kinfo_get_file and kinfo_get_vmmap for FreeBSD hosts.

FreeBSD systems have provided these functions in libutil since 7.1
release.  The most recent release without support is 6.4 released in
November of 2008.

This also requires libutil-freebsd on GNU/kFreeBSD systems.  I assume
that those systems have supported kinfo_get_file and kinfo_get_vmmap
over a similar timeframe.

gdb/ChangeLog:

	* configure.ac: Remove check for kinfo_getvmmap().
	* configure, config.in: Regenerate.
	* fbsd-nat.c (fbsd_read_mapping): Remove
	(fbsd_nat_target::find_memory_regions): Remove the procfs version.
	(fbsd_nat_target::info_proc): Assume kinfo_getfile() and
	kinfo_get_vmmap() are always present.

gdbsupport/ChangeLog:

	* common.m4 (GDB_AC_COMMON): Refactor checks for kinfo_getfile().
	* configure, config.in: Regenerate.