[FreeBSD] Add missing getnameinfo() flag values.

This patchs adds missing flag values for getnameinfo()
on FreeBSD, the following flags have been added from
the FreeBSD tree.

 /*
  * Flag values for getnameinfo()
  */
 #define	NI_NOFQDN	0x00000001
 #define	NI_NUMERICHOST	0x00000002
 #define	NI_NAMEREQD	0x00000004
 #define	NI_NUMERICSERV	0x00000008
 #define	NI_DGRAM	0x00000010
 #define	NI_NUMERICSCOPE	0x00000020

Signed-off-by: Valdemar Erk <valdemar@erk.io>