-extern void panic(const char *fmt, ...);
-extern int printk(const char *fmt, ...);
+#include "uml-config.h"
+
+/*
+ * The usual definition - copied here because the kernel provides its own,
+ * fancier, type-safe, definition. Using that one would require
+ * copying too much infrastructure for my taste, so userspace files
+ * get less checking than kernel files.
+ */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+/* This is to get size_t */
+#ifdef __KERNEL__
+#include <linux/types.h>
+#else
+#include <stddef.h>
+#endif
+
+extern void panic(const char *fmt, ...)
+ __attribute__ ((format (printf, 1, 2)));
+
+#ifdef UML_CONFIG_PRINTK
+extern int printk(const char *fmt, ...)
+ __attribute__ ((format (printf, 1, 2)));
+#else
+static inline int printk(const char *fmt, ...)
+{
+ return 0;
+}
+#endif
+