Use <atf_srcdir>/truncate_test.root_owned instead of /usr/bin/fpr as fpr does
not exist on FreeBSD

truncate_test.root_owned will be generated at build time and owned by root

In collaboration with: pho
Sponsored by: EMC / Isilon Storage Division
- Mark sig/signo __unused
- Do not provide a relative path via #include "h_macros.h"

Sponsored by: EMC / Isilon Storage Division
- Omit setrlimit_nthr testcase on FreeBSD (requires lwp.h, et al)
- Expect overflow with rlim_max at INT64_MAX, not UINT64_MAX (rlim_t is int64_t
on FreeBSD)

In collaboration with: pho
Sponsored by: EMC / Isilon Storage Division
Add limits.h #include for SSIZE_MAX

Sponsored by: EMC / Isilon Storage Division
Add limits.h #include for SSIZE_MAX

Sponsored by: EMC / Isilon Storage Division
Fix a typo (__FreeBSD__ -> __NetBSD__ when omitting setrlimit_nthr)
Mark signum __unused

Sponsored by: EMC / Isilon Storage Division