posix: fix binding of struct hostent. Make clear that gethostbyname(3) can return NULL.
posix: fix binding of struct hostent. Make clear that gethostbyname(3) can return NULL.

frida/vala,frida/vala,frida/vala,GNOME/vala,frida/vala,frida/vala,GNOME/vala,GNOME/vala,GNOME/vala