Generate sockdomainname() function with auto_if_type() instead
of auto_or_type.

The old parsing code would incorrectly decode a socket() call in the
ping6 program as:

CALL  socket(PF_PUP|PF_ECMA|PF_APPLETALK|PF_COIP|PF_SIP,SOCK_DGRAM,0)

The new parsing code decodes the same socket() call as:

CALL  socket(PF_INET6,SOCK_DGRAM,0)