Split off diskutil include

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.c b/fio.c
index 8c1502e..bdf9fd1 100644
--- a/fio.c
+++ b/fio.c
@@ -38,6 +38,7 @@
 #include "hash.h"
 #include "smalloc.h"
 #include "verify.h"
+#include "diskutil.h"
 
 unsigned long page_mask;
 unsigned long page_size;