mkdirat/mkdirat02.c: add new error number tests

Add ELOOP and EROFS error number tests for mkdirat(2)

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
lapi: Add mkdirat.h

Which defines mkdirat() if it's not present in system headers.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
syscalls/mkdirat01: Fixes.

* Cleanup

* Use tst_exit() instead of return 0
  (the test failure wasn't propagated out at all!)

* Make use of tst_tmpdir()

* Fix test iterations with -i

* Fix dir permissions (fixes test failure)

  the positive testcase was failing because the test had not
  search permission on the directory pointed to by dirfd

* Use lapi/mkdirat.h

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
syscalls/mkdirat02: Use lapi/mkdirat.h

Make use of lapi/mkdirat.h, add comment.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>