Copy Makefile.xxxx to Makefile and issue "make".  Use Makefile.post-1.3.22 
if the version of Linux you are using is Linux 1.3.22 or later.  These versions
have the recvmsg() and sendmsg() BSD socket services stubbed out (i.e., they'll
link, but when called they return a ENOTSUPPORTED errno value). Otherwise, use
Makefile.pre-1.3.22.

To obtain the version of Linux, issue the "uname -r" command and your
shell prompt.