[porter's handbook] remove references to fmake USES

The USES was removed in ports r452546 so there no more need to document
it.

en_US.ISO8859-1/books/porters-handbook/special/chapter.xml

@@ -518,28 +518,21 @@ IGNORE=	may not be redistributed because of licensing reasons. Please visit <rep
 
     <sect2 xml:id="using-make">
       <title><command>make</command>, <command>gmake</command>,
-	<command>fmake</command>, and <command>imake</command></title>
+	and <command>imake</command></title>
 
       <para>Several differing <literal>make</literal>
 	implementations exist.  Ported software often requires a
 	particular implementation, like <acronym>GNU</acronym>
 	<command>make</command>, known in &os; as
-	<command>gmake</command>, or <command>fmake</command>, the
-	legacy &os; <command>make</command>.</para>
+	<command>gmake</command>.</para>
 
       <para>If the port uses <application>GNU make</application>,
-	add <literal>gmake</literal> to <literal>USES</literal>.  If
-	the legacy &os; <command>make</command> is needed, add
-	<literal>fmake</literal> there.</para>
+	add <literal>gmake</literal> to
+	<literal>USES</literal>.</para>
 
       <para><varname>MAKE_CMD</varname> can be used to reference the
 	specific command configured by the <literal>USES</literal>
-	setting in the port's <filename>Makefile</filename>.  In
-	rare cases when more than one <literal>make</literal>
-	implementation is listed in <literal>USES</literal>, the
-	variables <varname>GMAKE</varname> (for the
-	<acronym>GNU</acronym> version) or <varname>FMAKE</varname>
-	(for the legacy &os; version) are available.
+	setting in the port's <filename>Makefile</filename>.
 	Only use <varname>MAKE_CMD</varname> within the
 	application <filename>Makefile</filename>s in
 	<varname>WRKSRC</varname> to call the