Shadow the flock pkg & add a noop filelock so that at least the solaris binary can be built

Without this the following error occurs:

$ GOOS=solaris go build .
# github.com/hashicorp/packer/vendor/github.com/gofrs/flock
vendor/github.com/gofrs/flock/flock_unix.go:28:22: undefined: syscall.LOCK_EX
vendor/github.com/gofrs/flock/flock_unix.go:39:22: undefined: syscall.LOCK_SH
vendor/github.com/gofrs/flock/flock_unix.go:56:12: undefined: syscall.Flock
vendor/github.com/gofrs/flock/flock_unix.go:66:12: undefined: syscall.Flock
vendor/github.com/gofrs/flock/flock_unix.go:96:12: undefined: syscall.Flock
vendor/github.com/gofrs/flock/flock_unix.go:96:42: undefined: syscall.LOCK_UN
vendor/github.com/gofrs/flock/flock_unix.go:118:21: undefined: syscall.LOCK_EX
vendor/github.com/gofrs/flock/flock_unix.go:130:21: undefined: syscall.LOCK_SH
vendor/github.com/gofrs/flock/flock_unix.go:149:9: undefined: syscall.Flock
vendor/github.com/gofrs/flock/flock_unix.go:149:44: undefined: syscall.LOCK_NB
vendor/github.com/gofrs/flock/flock_unix.go:149:44: too many errors

common/filelock/filelock.go

@@ -0,0 +1,11 @@
+// +build !solaris
+
+package filelock
+
+import "github.com/gofrs/flock"
+
+type Flock = flock.Flock
+
+func New(path string) *Flock {
+	return flock.New(path)
+}

common/filelock/filelock_solaris.go

@@ -0,0 +1,11 @@
+// build solaris
+
+package filelock
+
+// Flock is a noop on solaris for now.
+// TODO(azr): PR github.com/gofrs/flock for this.
+type Flock = Noop
+
+func New(string) *Flock {
+	return &Flock{}
+}

common/filelock/noop.go

@@ -0,0 +1,8 @@
+package filelock
+
+// this lock does nothing
+type Noop struct{}
+
+func (_ *Noop) Lock() (bool, error)    { return true, nil }
+func (_ *Noop) TryLock() (bool, error) { return true, nil }
+func (_ *Noop) Unlock() error          { return nil }

common/net/configure_port.go

@@ -8,8 +8,7 @@ import (
 	"net"
 	"strconv"
 
-	"github.com/gofrs/flock"
-
+	"github.com/hashicorp/packer/common/filelock"
 	"github.com/hashicorp/packer/packer"
 )
 
@@ -26,7 +25,7 @@ type Listener struct {
 	net.Listener
 	Port    int
 	Address string
-	lock    *flock.Flock
+	lock    *filelock.Flock
 }
 
 func (l *Listener) Close() error {
@@ -70,7 +69,7 @@ func (lc ListenRangeConfig) Listen(ctx context.Context) (*Listener, error) {
 			return nil, err
 		}
 
-		lock := flock.New(lockFilePath)
+		lock := filelock.New(lockFilePath)
 		locked, err := lock.TryLock()
 		if err != nil {
 			return nil, err

common/step_download.go

@@ -10,9 +10,9 @@ import (
 	"runtime"
 	"strings"
 
-	"github.com/gofrs/flock"
 	getter "github.com/hashicorp/go-getter"
 	urlhelper "github.com/hashicorp/go-getter/helper/url"
+	"github.com/hashicorp/packer/common/filelock"
 	"github.com/hashicorp/packer/helper/multistep"
 	"github.com/hashicorp/packer/packer"
 )
@@ -146,7 +146,7 @@ func (s *StepDownload) download(ctx context.Context, ui packer.Ui, source string
 	lockFile := targetPath + ".lock"
 
 	log.Printf("Acquiring lock for: %s (%s)", u.String(), lockFile)
-	lock := flock.New(lockFile)
+	lock := filelock.New(lockFile)
 	lock.Lock()
 	defer lock.Unlock()