Include netinet/in_systm.h in lm-sock.c, fixes LM-130.
Added check for netinet/in_systm.h and include it in lm-sock.c if it exists. It
fixes a build error on BSD.
<?xml version="1.0"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<book id="index" xmlns:xi="http://www.w3.org/2001/XInclude">
<bookinfo>
<title>Loudmouth Reference Manual</title>
</bookinfo>
<chapter>
<title>Loudmouth</title>
<xi:include href="xml/lm-connection.xml"/>
<xi:include href="xml/lm-error.xml"/>
<xi:include href="xml/lm-message.xml"/>
<xi:include href="xml/lm-message-handler.xml"/>
<xi:include href="xml/lm-message-node.xml"/>
<xi:include href="xml/lm-ssl.xml"/>
<xi:include href="xml/lm-proxy.xml"/>
<xi:include href="xml/lm-utils.xml"/>
</chapter>
</book>