tests: add acct.test

* tests/acct.c: New file.
* tests/acct.test: New test.
* tests/.gitignore: Add acct.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(TESTS): Add acct.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index c6a94d8..4b9595d 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -6,6 +6,7 @@
 *.tmp.*
 *.trs
 _newselect
+acct
 adjtimex
 aio
 alarm