build: move package sources from src/pkg to src

Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.

src/os/signal/signal_unix.go

@@ -0,0 +1,53 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
+
+package signal
+
+import (
+	"os"
+	"syscall"
+)
+
+// In assembly.
+func signal_disable(uint32)
+func signal_enable(uint32)
+func signal_recv() uint32
+
+func loop() {
+	for {
+		process(syscall.Signal(signal_recv()))
+	}
+}
+
+func init() {
+	signal_enable(0) // first call - initialize
+	go loop()
+}
+
+const (
+	numSig = 65 // max across all systems
+)
+
+func signum(sig os.Signal) int {
+	switch sig := sig.(type) {
+	case syscall.Signal:
+		i := int(sig)
+		if i < 0 || i >= numSig {
+			return -1
+		}
+		return i
+	default:
+		return -1
+	}
+}
+
+func enableSignal(sig int) {
+	signal_enable(uint32(sig))
+}
+
+func disableSignal(sig int) {
+	signal_disable(uint32(sig))
+}