Switch NetBSD from paccept(2) to accept4(2)

[krytarowski]

Summary

NetBSD 8.0 will ship with accept4(2) in libc wrapping paccept(2).

This change reduces needless difference with other platforms.

Older versions of NetBSD will not be supported.

No functional change.

Sponsored by <The NetBSD Foundation>

source/Host/common/Socket.cpp

if (fd >= 0 && !child_processes_inherit) {
     close(fd);
   }
   return fd;
 #elif defined(SOCK_CLOEXEC)
   int flags = 0;
   if (!child_processes_inherit) {
     flags |= SOCK_CLOEXEC;
   }
-#if defined(__NetBSD__)
-  NativeSocket fd = ::paccept(sockfd, addr, addrlen, nullptr, flags);
-#else
   NativeSocket fd = ::accept4(sockfd, addr, addrlen, flags);
-#endif
 #else
   NativeSocket fd = ::accept(sockfd, addr, addrlen);
 #endif
   if (fd == kInvalidSocketValue)
     SetLastError(error);
   return fd;
 }