- Remove obsolete 'Threading Libraries' paragraph

Reviewed by:	mat, bcr
Approved by:	mat (portmgr), bcr

Differential Revision:	https://reviews.freebsd.org/D997

en_US.ISO8859-1/books/porters-handbook/porting-dads/chapter.xml

@@ -321,25 +321,6 @@ exec %%LOCALBASE%%/bin/java -jar %%DATADIR%%/foo.jar "$@"</programlisting>
     <programlisting>CFLAGS+= -DHAVE_SOUND</programlisting>
   </sect1>
 
-  <sect1 xml:id="dads-pthread">
-    <title>Threading Libraries</title>
-
-    <para>The threading library must be linked to the binaries using
-      a special flag <literal>-pthread</literal> on &os;.  If a port
-      insists on linking <literal>-lpthread</literal> directly, patch
-      it to use <literal>-pthread</literal>.</para>
-
-    <note>
-      <para>If building the port errors out with
-	<literal>unrecognized option '-pthread'</literal>, it may be
-	desirable to use <command>cc</command> as linker by setting
-	<varname>CONFIGURE_ENV</varname> to
-	<literal>LD=${CC}</literal>.  The <literal>-pthread</literal>
-	option is not supported by <command>ld</command>
-	directly.</para>
-    </note>
-  </sect1>
-
   <sect1 xml:id="dads-feedback">
     <title>Feedback</title>