renameat2 syscall: turn EEXIST into ENOTEMPTY

XFS is returning EEXIST rather than ENOTEMPTY for several of
these rename tests. The rename man page says this about the errors:

       ENOTEMPTY or EEXIST
              newpath is a nonempty directory, that is, contains
              entries other than "." and "..".

Which implies that both errors are valid and so the test should pass
in either case.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

src/renameat2.c

@@ -92,6 +92,15 @@ int main(int argc, char *argv[])
 			else
 				return 0;
 		}
+		/*
+		 * Turn EEXIST into ENOTEMPTY.  E.g. XFS uses EEXIST, and that
+		 * is also accepted by the standards.
+		 *
+		 * This applies only to plain rename (flags == 0).
+		 */
+		if (!flags && errno == EEXIST)
+			errno = ENOTEMPTY;
+
 		perror("");
 		return 1;
 	}