Add nologin.

toys/other/nologin.c

diff --git a/toys/other/nologin.c b/toys/other/nologin.c
new file mode 100644
index 0000000..851cd79
--- /dev/null
+++ b/toys/other/nologin.c
@@ -0,0 +1,24 @@
+/* nologin.c - False with a message.
+ *
+ * Copyright 2025 Rob Landley <rob@landley.net>
+ *
+ * No standard.
+
+USE_NOLOGIN(NEWTOY(nologin, 0, TOYFLAG_BIN|TOYFLAG_NOHELP))
+
+config NOLOGIN
+  bool "nologin"
+  default y
+  help
+    usage: nologin
+
+    Print /etc/nologin.txt and return failure.
+*/
+
+#include "toys.h"
+
+void nologin_main(void)
+{
+  toys.exitval = 1;
+  puts(readfile("/etc/nologin.txt", 0, 0) ? : toys.which->name);
+}