Implement two basic "strace -f" tests

* Makefile.am (SUBDIRS): Add tests.
* configure.ac (AC_CONFIG_FILES): Add tests/Makefile.
* tests/.gitignore: New file.
* tests/Makefile.am: Likewise.
* tests/init.sh: Likewise.
* tests/ptrace_setoptions: Likewise.
* tests/strace-f: Likewise.
diff --git a/configure.ac b/configure.ac
index 5d56dab..ca1694b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -309,5 +309,5 @@
 
 AC_PATH_PROG([PERL], [perl])
 
-AC_CONFIG_FILES([Makefile])
+AC_CONFIG_FILES([Makefile tests/Makefile])
 AC_OUTPUT