No stdio.h on Mini-OS, so use cdefs.h again there.

src/cdefs-compat.h

@@ -1,11 +1,16 @@
 #ifndef _CDEFS_COMPAT_H_
 #define	_CDEFS_COMPAT_H_
 
+#ifdef __MINIOS__
+/* No stdio.h on Mini-OS. */
+#include <sys/cdefs.h>
+#else
 /*
  * We cannot be certain that this operating system has <sys/cdefs.h>.
  * Instead, include a header file that is likely to pull in this header.
  */
 #include <stdio.h>
+#endif
 
 #if defined(__cplusplus)
 #define	__BEGIN_DECLS	extern "C" {