Correct the setitimer interceptor on NetBSD
itimerval can contain padding that may be legitimately uninitialized.
On NetBSD there are four integers of type "long, int, long, int", the
int argument stands for __sanitizer_suseconds_t. Compiler adds extra
padding in this layout.
Check every field of struct itimerval separately.
Define sanitizer_suseconds_t as long on FreeBSD, Linux and SmartOS,
and int on NetBSD. Define sanitizer_timeval and __sanitizer_itimerval.
Sponsored by <The NetBSD Foundation>
Reviewers: eugenis, joerg, vitalybuka
Reviewed By: vitalybuka
Subscribers: emaste, kubamracek, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D41502