define NI_MAXHOST per system

- under openbsd/bitrig it is 256
- change type to `size_t` where system have `getnameinfo()` with
  `hostlen` as `size_t`

src/unix/bsd/apple/mod.rs

@@ -809,6 +809,8 @@ pub const VT1: ::c_int  = 0x00010000;
 pub const IUTF8: ::tcflag_t = 0x00004000;
 pub const CRTSCTS: ::tcflag_t = 0x00030000;
 
+pub const NI_MAXHOST: ::socklen_t = 1025;
+
 extern {
     pub fn getnameinfo(sa: *const ::sockaddr,
                        salen: ::socklen_t,

src/unix/bsd/freebsdlike/mod.rs

@@ -557,6 +557,8 @@ pub const ST_NOSUID: ::c_ulong = 2;
 
 pub const HW_AVAILCPU: ::c_int = 25;
 
+pub const NI_MAXHOST: ::size_t = 1025;
+
 extern {
     pub fn getnameinfo(sa: *const ::sockaddr,
                        salen: ::socklen_t,

src/unix/bsd/mod.rs

@@ -147,8 +147,6 @@ pub const IPV6_V6ONLY: ::c_int = 27;
 
 pub const ST_RDONLY: ::c_ulong = 1;
 
-pub const NI_MAXHOST: ::socklen_t = 1025;
-
 pub const CTL_HW: ::c_int = 6;
 pub const HW_NCPU: ::c_int = 3;
 

src/unix/bsd/openbsdlike/bitrig.rs

@@ -217,6 +217,8 @@ pub const KERN_PROC_ARGS: ::c_int = 55;
 
 pub const TMP_MAX : ::c_uint = 0x7fffffff;
 
+pub const NI_MAXHOST: ::size_t = 256;
+
 extern {
     pub fn getnameinfo(sa: *const ::sockaddr,
                        salen: ::socklen_t,

src/unix/bsd/openbsdlike/netbsd.rs

@@ -322,6 +322,8 @@ pub const CRTSCTS: ::tcflag_t = 0x00010000;
 
 pub const TMP_MAX : ::c_uint = 308915776;
 
+pub const NI_MAXHOST: ::socklen_t = 1025;
+
 extern {
     pub fn getnameinfo(sa: *const ::sockaddr,
                        salen: ::socklen_t,

src/unix/bsd/openbsdlike/openbsd.rs

@@ -216,6 +216,8 @@ pub const KERN_PROC_ARGS: ::c_int = 55;
 
 pub const TMP_MAX : ::c_uint = 0x7fffffff;
 
+pub const NI_MAXHOST: ::size_t = 256;
+
 // syscall numbers
 pub const SYS_getentropy: ::c_int = 7;