Add strong madvise() hint for cache pruning

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/os/os-solaris.h b/os/os-solaris.h
index 943d387..5029d38 100644
--- a/os/os-solaris.h
+++ b/os/os-solaris.h
@@ -108,4 +108,8 @@
  */
 #define FIO_MAX_CPUS			16384
 
+#ifdef MADV_FREE
+#define FIO_MADV_FREE	MADV_FREE
+#endif
+
 #endif