internal/socket, lif: add missing //go:build lines

Change-Id: I62c10c4ddd5cc7a037795db4bcf015ccf9bccb1f
Reviewed-on: https://go-review.googlesource.com/c/net/+/362914
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/internal/socket/empty.s b/internal/socket/empty.s
index bff0231..90ab4ca 100644
--- a/internal/socket/empty.s
+++ b/internal/socket/empty.s
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build darwin && go1.12
 // +build darwin,go1.12
 
 // This exists solely so we can linkname in symbols from syscall.
diff --git a/lif/address.go b/lif/address.go
index afb957f..34b6432 100644
--- a/lif/address.go
+++ b/lif/address.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/address_test.go b/lif/address_test.go
index a25f10b..2fa1545 100644
--- a/lif/address_test.go
+++ b/lif/address_test.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/binary.go b/lif/binary.go
index 738a94f..f31ca3a 100644
--- a/lif/binary.go
+++ b/lif/binary.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/defs_solaris.go b/lif/defs_solaris.go
index 02c1998..695119e 100644
--- a/lif/defs_solaris.go
+++ b/lif/defs_solaris.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build ignore
 // +build ignore
 
 // +godefs map struct_in_addr [4]byte /* in_addr */
diff --git a/lif/lif.go b/lif/lif.go
index 6e81f81..95c7d25 100644
--- a/lif/lif.go
+++ b/lif/lif.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 // Package lif provides basic functions for the manipulation of
diff --git a/lif/link.go b/lif/link.go
index 913a53e..f1af130 100644
--- a/lif/link.go
+++ b/lif/link.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/link_test.go b/lif/link_test.go
index 0cb9b95..d352849 100644
--- a/lif/link_test.go
+++ b/lif/link_test.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/sys.go b/lif/sys.go
index c896041..d0b532d 100644
--- a/lif/sys.go
+++ b/lif/sys.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif
diff --git a/lif/syscall.go b/lif/syscall.go
index aadab2e..8d03b4a 100644
--- a/lif/syscall.go
+++ b/lif/syscall.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build solaris
 // +build solaris
 
 package lif