tests: add xattr.test

* tests/xattr.c: New file.
* tests/xattr.expected: Likewise.
* tests/xattr.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add xattr.
(TESTS): Add xattr.test.
(EXTRA_DIST): Add xattr.expected.
* tests/.gitignore: Add xattr.
5 files changed