diff --git a/libfuse/lib/helper.c b/libfuse/lib/helper.c
index 8b04975e..f06a5694 100644
--- a/libfuse/lib/helper.c
+++ b/libfuse/lib/helper.c
@@ -55,9 +55,9 @@ struct fuse_opt fuse_helper_opts[] =
 
 static
 int
-fuse_helper_opt_proc(void *data,
-                     const char *arg,
-                     int key,
+fuse_helper_opt_proc(void             *data,
+                     const char       *arg,
+                     int               key,
                      struct fuse_args *outargs)
 {
   struct helper_opts *hopts = data;