Add information about contributing to the C99/Posix compliance project.

Suggested by: wollman

en_US.ISO8859-1/articles/contributing/article.sgml

@@ -176,6 +176,20 @@ FreeBSD Entities//EN"> %freebsd;
 	    easier when they bring out the next version)</para>
 	</listitem>
 
+	<listitem>
+	  <para>Get copies of formal standards like POSIX.  You can
+	    get some links about these standards at the <ulink
+	    url="http://www.FreeBSD.org/projects/c99/index.html">FreeBSD
+	    C99 & Posix Standards Conformance Project</ulink> web
+	    site. Compare FreeBSD's behavior to that required by the
+	    standard. If the behavior differs, particularly in subtle
+	    or obscure corners of the specification, send in a PR
+	    about it.  If you are able, figure out how to fix it and
+	    include a patch in the PR.  If you think the standard is
+	    wrong, ask the standards body to consider the
+	    question.</para>
+	</listitem>
+
 	<listitem>
 	  <para>Suggest further tasks for this list!</para>
 	</listitem>