Fix numerous bigs in the FreeBSD backend

* Correct calculation of CPU time.
* Fix a bug on newer versions of FreeBSD where computing the process map leads
to a tight error loop.
* Add support for the new procstat API to obtain the list of open files and
cwd.
* Use kvm_openfiles instead of kvm_open to better handle error messages.
* Split some modules out into non-suid modules.
* Properly determine the number of CPUs.

https://bugzilla.gnome.org/show_bug.cgi?id=605431

sysdeps/freebsd/sysinfo.c

@@ -45,8 +45,8 @@ init_sysinfo (glibtop *server)
 
 	glibtop_init_s (&server, GLIBTOP_SYSDEPS_CPU, 0);
 
-	len = sizeof (ncpus);
-	sysctlbyname ("hw.ncpu", &ncpus, &len, NULL, 0);
+	ncpus = server->ncpu + 1;
+
 	len = 0;
 	sysctlbyname ("hw.model", NULL, &len, NULL, 0);
 	model = g_malloc (len);