internal/syscall: move to unix subdirectory

Move the single file from internal/syscall to internal/syscall/unix,
to match the golang.org/x/sys layout.

Change-Id: I2fb2832b4cb22efc7666bd276f5401ac3e73dc40
Reviewed-on: https://go-review.googlesource.com/8972Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

src/crypto/rand/rand_linux.go

@@ -5,7 +5,7 @@
 package rand
 
 import (
-	"internal/syscall"
+	"internal/syscall/unix"
 	"sync"
 )
 
@@ -25,7 +25,7 @@ func pickStrategy() {
 	// - the machine has no entropy available (early boot + no hardware
 	//   entropy source?) and we want to avoid blocking later.
 	var buf [1]byte
-	n, err := syscall.GetRandom(buf[:], syscall.GRND_NONBLOCK)
+	n, err := unix.GetRandom(buf[:], unix.GRND_NONBLOCK)
 	useSyscall = n == 1 && err == nil
 }
 
@@ -34,6 +34,6 @@ func getRandomLinux(p []byte) (ok bool) {
 	if !useSyscall {
 		return false
 	}
-	n, err := syscall.GetRandom(p, 0)
+	n, err := unix.GetRandom(p, 0)
 	return n == len(p) && err == nil
 }

src/go/build/deps_test.go

@@ -279,7 +279,7 @@ var pkgDeps = map[string][]string{
 	// Random byte, number generation.
 	// This would be part of core crypto except that it imports
 	// math/big, which imports fmt.
-	"crypto/rand": {"L4", "CRYPTO", "OS", "math/big", "syscall", "internal/syscall"},
+	"crypto/rand": {"L4", "CRYPTO", "OS", "math/big", "syscall", "internal/syscall/unix"},
 
 	// Mathematical crypto: dependencies on fmt (L4) and math/big.
 	// We could avoid some of the fmt, but math/big imports fmt anyway.

src/internal/syscall/getrandom_linux.go → src/internal/syscall/unix/getrandom_linux.go

@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package syscall
+package unix
 
 import (
 	"runtime"
 	"sync/atomic"
-	stdsyscall "syscall"
+	"syscall"
 	"unsafe"
 )
 
@@ -36,20 +36,20 @@ const (
 // See https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c6e9d6f38894798696f23c8084ca7edbf16ee895
 func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
 	if randomTrap == 0 {
-		return 0, stdsyscall.ENOSYS
+		return 0, syscall.ENOSYS
 	}
 	if len(p) == 0 {
 		return 0, nil
 	}
 	if atomic.LoadInt32(&randomUnsupported) != 0 {
-		return 0, stdsyscall.ENOSYS
+		return 0, syscall.ENOSYS
 	}
-	r1, _, errno := stdsyscall.Syscall(randomTrap,
+	r1, _, errno := syscall.Syscall(randomTrap,
 		uintptr(unsafe.Pointer(&p[0])),
 		uintptr(len(p)),
 		uintptr(flags))
 	if errno != 0 {
-		if errno == stdsyscall.ENOSYS {
+		if errno == syscall.ENOSYS {
 			atomic.StoreInt32(&randomUnsupported, 1)
 		}
 		return 0, errno