lang: Unnested the core package from the functions dir

The core package could contain non-functions, so we might as well move
it upwards.

lang/core/sys/load_fact_posix.go

@@ -0,0 +1,45 @@
+// Mgmt
+// Copyright (C) 2013-2024+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+//go:build !darwin
+
+package coresys
+
+import (
+	"syscall"
+)
+
+const (
+	// LoadScale factor scales the output from sysinfo to the correct float
+	// value.
+	LoadScale = 65536 // XXX: is this correct or should it be 65535?
+)
+
+// load returns the system load averages for the last minute, five minutes and
+// fifteen minutes. Calling this more often than once every five seconds seems
+// to be unnecessary, since the kernel only updates these values that often.
+// TODO: is the kernel update interval configurable?
+func load() (one, five, fifteen float64, err error) {
+	var sysinfo syscall.Sysinfo_t
+	if err = syscall.Sysinfo(&sysinfo); err != nil {
+		return
+	}
+	one = float64(sysinfo.Loads[0]) / LoadScale
+	five = float64(sysinfo.Loads[1]) / LoadScale
+	fifteen = float64(sysinfo.Loads[2]) / LoadScale
+	return
+}