tests: add sigaltstack.test

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