Update Darwin defaults to useable values

The current Darwin defaults are not supported on Darwin and do not allow
for successfully pulling or running containers. Switch to defaults that
will work on Darwin based on new features in containerd 2.2.

Signed-off-by: Derek McGowan <derek@mcg.dev>

defaults/defaults_darwin.go

@@ -17,6 +17,23 @@
 package defaults
 
 const (
-	// DefaultRuntime would be a multiple of choices, thus empty
-	DefaultRuntime = ""
+	// DefaultRuntime is the default darwin runtime for running containers
+	DefaultRuntime = "io.containerd.nerdbox.v1"
+	// DefaultAddress is the default unix socket address
+	DefaultAddress = "/var/run/containerd/containerd.sock"
+	// DefaultDebugAddress is the default unix socket address for pprof data
+	DefaultDebugAddress = "/var/run/containerd/debug.sock"
+	// DefaultFIFODir is the default location used by client-side cio library
+	// to store FIFOs.
+	DefaultFIFODir = "/var/run/containerd/fifo"
+	// DefaultSnapshotter will set the default snapshotter for the platform.
+	// Since mounts are not supported on Darwin, use erofs as the default
+	// which does not require mount support.
+	DefaultSnapshotter = "erofs"
+	// DefaultStateDir is the default location used by containerd to store
+	// transient data
+	DefaultStateDir = "/var/run/containerd"
+	// DefaultDiffer will set the default differ for the platform, use the
+	// erofs differ which does not require mount support.
+	DefaultDiffer = "erofs"
 )

defaults/defaults_unix_other.go

@@ -1,4 +1,4 @@
-//go:build unix && !linux
+//go:build unix && !linux && !darwin
 
 /*
    Copyright The containerd Authors.