Stub out FreeBSD support for Nomad

Compiles, but is not functional (yet).

client/allocdir/alloc_dir_freebsd.go

@@ -0,0 +1,26 @@
+package allocdir
+
+import (
+	"syscall"
+)
+
+// Hardlinks the shared directory. As a side-effect the shared directory and
+// task directory must be on the same filesystem.
+func (d *AllocDir) mountSharedDir(dir string) error {
+	return syscall.Link(d.SharedDir, dir)
+}
+
+func (d *AllocDir) unmountSharedDir(dir string) error {
+	return syscall.Unlink(dir)
+}
+
+// MountSpecialDirs mounts the dev and proc file system on the chroot of the
+// task. It's a no-op on FreeBSD right now.
+func (d *AllocDir) MountSpecialDirs(taskDir string) error {
+	return nil
+}
+
+// unmountSpecialDirs unmounts the dev and proc file system from the chroot
+func (d *AllocDir) unmountSpecialDirs(taskDir string) error {
+	return nil
+}

client/fingerprint/storage_unix.go

@@ -1,4 +1,4 @@
-// +build darwin linux
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package fingerprint