support for kfreebsd and old FreeBSD systems.

cachedel.c

 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#if __POSIX_VISIBLE < 200112
+#define POSIX_FADV_NORMAL       0       /* no special treatment */
+#define POSIX_FADV_RANDOM       1       /* expect random page references */
+#define POSIX_FADV_SEQUENTIAL   2       /* expect sequential page references */
+#define POSIX_FADV_WILLNEED     3       /* will need these pages */
+#define POSIX_FADV_DONTNEED     4       /* dont need these pages */
+#define POSIX_FADV_NOREUSE      5       /* access data only once */
+#endif
 #include <error.h>
 #include <stdio.h>
 #include <stdlib.h>