Index: head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
===================================================================
--- head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
+++ head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
@@ -4342,7 +4342,7 @@
 	  <emphasis>not</emphasis> selected.  For example:</para>
 
 	<programlisting>OPTIONS_DEFINE=	OPT1
-OPT1_CMAKE_ON=	-DTEST:BOOL=true
+OPT1_CMAKE_ON=	-DTEST:BOOL=true -DDEBUG:BOOL=true
 OPT1_CMAKE_OFF=	-DOPTIMIZE:BOOL=true</programlisting>
 
 	<para>is equivalent to:</para>
@@ -4352,10 +4352,56 @@
 .include &lt;bsd.port.options.mk&gt;
 
 .if ${PORT_OPTIONS:MOPT1}
-CMAKE_ARGS+=	-DTEST:BOOL=true
+CMAKE_ARGS+=	-DTEST:BOOL=true -DDEBUG:BOOL=true
 .else
 CMAKE_ARGS+=	-DOPTIMIZE:BOOL=true
 .endif</programlisting>
+
+	<para>See <xref linkend="options-cmake_bool"/> for a shorter
+	  helper when the value is boolean.</para>
+      </sect3>
+
+      <sect3 xml:id="options-cmake_bool">
+	<title><varname><replaceable>OPT</replaceable>_CMAKE_BOOL</varname>
+	  and
+	  <varname><replaceable>OPT</replaceable>_CMAKE_BOOL_OFF</varname></title>
+
+	<para>When option <replaceable>OPT</replaceable> is selected,
+	  for each <replaceable>entry</replaceable> in
+	  <varname><replaceable>OPT</replaceable>_CMAKE_BOOL</varname>
+	  then
+	  <literal>-D<replaceable>entry</replaceable>:BOOL=true</literal>
+	  is appended to <varname>CMAKE_ARGS</varname>.  When option
+	  <replaceable>OPT</replaceable> is <emphasis>not</emphasis>
+	  selected,
+	  <literal>-D<replaceable>entry</replaceable>:BOOL=false</literal>
+	  is appended to <varname>CONFIGURE_ARGS</varname>.
+	  <varname><replaceable>OPT</replaceable>_CMAKE_BOOL_OFF</varname>
+	  is the oposite,
+	  <literal>-D<replaceable>entry</replaceable>:BOOL=false</literal>
+	  is appended to <varname>CMAKE_ARGS</varname> when the option
+	  is selected, and
+	  <literal>-D<replaceable>entry</replaceable>:BOOL=true</literal>
+	  when the option is <emphasis>not</emphasis> selected.  For
+	  example:</para>
+
+	<programlisting>OPTIONS_DEFINE=	OPT1
+OPT1_CMAKE_BOOL=	TEST DEBUG
+OPT1_CMAKE_BOOL_OFF=	OPTIMIZE</programlisting>
+
+	<para>is equivalent to:</para>
+
+	<programlisting>OPTIONS_DEFINE=	OPT1
+
+.include &lt;bsd.port.options.mk&gt;
+
+.if ${PORT_OPTIONS:MOPT1}
+CMAKE_ARGS+=	-DTEST:BOOL=true -DDEBUG:BOOL=true \
+		-DOPTIMIZE:BOOL=false
+.else
+CMAKE_ARGS+=	-DTEST:BOOL=false -DDEBUG:BOOL=false \
+		-DOPTIMIZE:BOOL=true
+.endif</programlisting>
       </sect3>
 
       <sect3 xml:id="options-qmake_on">