fix build on OpenBSD

fs_other.go

@@ -0,0 +1,20 @@
+//go:build windows || openbsd
+
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/urfave/cli/v3"
+)
+
+var fsCmd = &cli.Command{
+	Name:                      "fs",
+	Usage:                     "mount a FUSE filesystem that exposes Nostr events as files.",
+	Description:               `doesn't work on Windows and OpenBSD.`,
+	DisableSliceFlagSeparator: true,
+	Action: func(ctx context.Context, c *cli.Command) error {
+		return fmt.Errorf("this doesn't work on Windows and OpenBSD.")
+	},
+}