unix: add S_IRWXG and S_IRWXO to FreeBSD types

I found this during https://github.com/DataDog/datadog-agent/pull/2079

Change-Id: I51d57e7e3cedb8b23e720bc03f38504dc0ad063d
GitHub-Last-Rev: 4e1c193db8bfc9174f630903bfc26e5532555309
GitHub-Pull-Request: golang/sys#13
Reviewed-on: https://go-review.googlesource.com/126620
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

unix/types_freebsd.go

@@ -204,6 +204,8 @@ const ( // Directory mode bits
 	S_IRUSR  = C.S_IRUSR
 	S_IWUSR  = C.S_IWUSR
 	S_IXUSR  = C.S_IXUSR
+	S_IRWXG  = C.S_IRWXG
+	S_IRWXO  = C.S_IRWXO
 )
 
 type Stat_t C.struct_stat8

unix/ztypes_freebsd_386.go

@@ -71,6 +71,8 @@ const (
 	S_IRUSR  = 0x100
 	S_IWUSR  = 0x80
 	S_IXUSR  = 0x40
+	S_IRWXG  = 0x38
+	S_IRWXO  = 0x7
 )
 
 type Stat_t struct {

unix/ztypes_freebsd_amd64.go

@@ -71,6 +71,8 @@ const (
 	S_IRUSR  = 0x100
 	S_IWUSR  = 0x80
 	S_IXUSR  = 0x40
+	S_IRWXG  = 0x38
+	S_IRWXO  = 0x7
 )
 
 type Stat_t struct {

unix/ztypes_freebsd_arm.go

@@ -73,6 +73,8 @@ const (
 	S_IRUSR  = 0x100
 	S_IWUSR  = 0x80
 	S_IXUSR  = 0x40
+	S_IRWXG  = 0x38
+	S_IRWXO  = 0x7
 )
 
 type Stat_t struct {