Support FreeBSD on pkg/mount

Docker-DCO-1.1-Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.com> (github: kzys)

mount/flags_freebsd.go

@@ -0,0 +1,28 @@
+// +build freebsd,cgo
+
+package mount
+
+/*
+#include <sys/mount.h>
+*/
+import "C"
+
+const (
+	RDONLY      = C.MNT_RDONLY
+	NOSUID      = C.MNT_NOSUID
+	NOEXEC      = C.MNT_NOEXEC
+	SYNCHRONOUS = C.MNT_SYNCHRONOUS
+	NOATIME     = C.MNT_NOATIME
+
+	BIND        = 0
+	DIRSYNC     = 0
+	MANDLOCK    = 0
+	NODEV       = 0
+	NODIRATIME  = 0
+	PRIVATE     = 0
+	RBIND       = 0
+	RELATIVE    = 0
+	RELATIME    = 0
+	REMOUNT     = 0
+	STRICTATIME = 0
+)