Add OS agnostic RAND_MAX

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/os/os-solaris.h b/os/os-solaris.h
index 9e243e8..759f3c1 100644
--- a/os/os-solaris.h
+++ b/os/os-solaris.h
@@ -9,7 +9,8 @@
 #define FIO_HAVE_FALLOCATE
 #define FIO_HAVE_POSIXAIO_FSYNC
 
-#define OS_MAP_ANON		(MAP_ANON)
+#define OS_MAP_ANON		MAP_ANON
+#define OS_RAND_MAX		2147483648UL
 
 struct solaris_rand_seed {
 	unsigned short r[3];