FreeBSD has pthread_np.h, which is used for consolidating all non-POSIX functions, but NetBSD doesn't have this concept. Make _np functions work seamlessly when ported from NetBSD to FreeBSD
$FreeBSD$ libnetbsd is a thin compatibility layer intended to allow a limited set of NetBSD software to compile as part of the FreeBSD build with little or no modification. It is built as a static library and not installed for general use. Likewise, its header files are not installed.