We need libgen.h for basename()

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/verify.c b/verify.c
index 14d3213..b4434b9 100644
--- a/verify.c
+++ b/verify.c
@@ -6,6 +6,7 @@
 #include <string.h>
 #include <assert.h>
 #include <pthread.h>
+#include <libgen.h>
 
 #include "fio.h"
 #include "verify.h"