fuse: use flexible array in fuse.h

Use the ISO C standard compliant form instead of the gcc extension in the
interface definition.
Reported-by: Shachar Sharon <ssnail@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

include/linux/fuse.h

@@ -593,7 +593,7 @@ struct fuse_dirent {
 	__u64	off;
 	__u32	namelen;
 	__u32	type;
-	char name[0];
+	char name[];
 };
 
 #define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, name)